Types of Stone & Other Facts | Granite | Marble | Limestone Types of Stone & Other Facts TYPES OF STONE: The familiar stone types that are used today are identified through four categories: Sedimentary, Metamorphic, Igneous and Man-made stone. I. Sedimentary stone came from organic elements such as glaciers, rivers, wind, oceans, and plants. Tiny sedimentary pieces broke off form these elements and accumulated to form rock beds. They were bonded through millions of years of heat and pressure. a)Limestone: Mainly consists of calcite. It does not show such graining or crystalline structure. It has a smooth granular surface. Varies in hardness. Some dense limestone can be polished. Common colors are black, grey, white, yellow or brown. It is more likely to stain than marble. Limestone is known to contain lime from sea water. b)Sandstone: Is a very durable formation of quartz grains (sand). Usually formed in light brown or red colors. Categorized by the most popular sandstone bonding agents such as silica, calcium, clay, and iron oxide. c)Soapstone: A very soft stone made of a variety of talc.

It is a dense mineral that wears well and is often resistant to oxide. d)Fossilstone: Considered a limestone that contains natural fossils such as sea-shells and plants. e)Travertine: Usually a cream or reddish color. It is formed through the accumulation of calcite from hot springs. It contains holes that were formed from water flowing through the stone. These holes are often filled with synthetic resins or cements. Requires a lot of maintenance if the holes are not filled. Classified as a limestone and a marble. II. Metamorphic stones originate from a natural form of one type of stone to another type through the mixture of heat, pressure, and minerals. The change may be a development of a crystalline formation, a texture change, or a color change. a)Marble: A recrystallized limestone that formed when the limestone softened from heat and pressure and recrystallized into marble where a mineral change occurred. The main consistency is calcium and dolomite. Ranges in many colors and is usually heavily veined and shows grains. Hardness rates from 2.5 to 5 on the MOH Scale. Marble is classified into three categories: 1.

Dolomite: If it has more than 40% magnesium carbonates. 2. Magnesium: If it has between 5% and 40% magnesium 3. Calcite: If it has less than 5% magnesium carbonate. b)Slate: Fine grained metamorphic stone that is formed from clay, sedimentary rock shale, and sometimes quartz. Very thin and can break easily. Usually in black, gray or green. c)Serpentine: Identified by its marks, which look like the skin of a serpent. Most popular colors are green and brown. Hardness rates from 2.5 to 4 on the MOH scale. Contains serpentine minerals and magnesium, and has an igneous origin. Does not always react well to recrystallization or diamond polishing. III. Igneous stones are mainly formed through volcanic material such as magma. Underneath the Earth's surface, liquid magma cooled and solidified. Mineral gases and liquids penetrated into the stone and created new crystalline formations with various colors. a)Granite: Primarily made of Quartz (35%), Feldspar (45%) and Potassium. Usually comes in dark colors and contains very little calcite, if any.

Provides a heavy crystalline and granular appearance with mineral grains. It is a very hard material and easier to maintain than marble. Yet, it is still porous and will stain. There are different types of granite depending on the percentage mix of quartz, mica and feldspar. Black granite is known as an Anorthosite. It contains very little quartz and feldspar and has a different composition than true granite. IV. Man Made Stones are derived of unnatural mixtures such as resin or cement with the additive of stone chips. a)Terrazzo: Marble and granite chips embedded in a cement composition. b)Agglomerate or conglomerate: Marble chips embedded in a colored resin composition. c)Cultured or Faux Marble: A mix of resins that are painted or mixed with a paint to looks like marble. STONE NAMES Currently, there are many companies around the world that use generic names to identify different types of stone. This has created a problem for the stone maintenance industry. The original names were in Italian. Usually the name consists of two parts. The first part describes the color and second part describes the name from where the stone was quarried.

Marble: Metamorphic Rock: Pictures, Definition, Properties Marble A non-foliated metamorphic rock that forms when limestone is subjected to heat and pressure. Pink Marble: A piece of pink marble about four inches (ten centimeters) across. The pink color is most likely derived from iron. Image by NASA. What is Marble? Marble is a metamorphic rock that forms when limestone is subjected to the heat and pressure of metamorphism. It is composed primarily of the mineral calcite (CaCO3) and usually contains other minerals, such as clay minerals, micas, quartz , pyrite , iron oxides, and graphite . Under the conditions of metamorphism, the calcite in the limestone recrystallizes to form a rock that is a mass of interlocking calcite crystals. A related rock, dolomitic marble, is produced when dolostone is subjected to heat and pressure. Photo Gallery: The Many Uses of Marble Ruby in Marble: Marble is often the host rock for corundum, spinel, and other gem minerals. This specimen is a piece of white marble with a large red ruby crystal from Afghanistan. Specimen is about 1 1/4 inches across (about 3 centimeters).

Specimen and photo by Arkenstone / . How Does Marble Form? Most marble forms at convergent plate boundaries where large areas of Earth's crust are exposed to regional metamorphism. Some marble also forms by contact metamorphism when a hot magma body heats adjacent limestone or dolostone. Before metamorphism, the calcite in the limestone is often in the form of lithified fossil material and biological debris. During metamorphism, this calcite recrystallizes and the texture of the rock changes. In the early stages of the limestone-to-marble transformation, the calcite crystals in the rock are very small. In a freshly-broken hand specimen, they might only be recognized as a sugary sparkle of light reflecting from their tiny cleavage faces when the rock is played in the light. As metamorphism progresses, the crystals grow larger and become easily recognizable as interlocking crystals of calcite. Recrystallization obscures the original fossils and sedimentary structures of the limestone. It also occurs without forming foliation, which normally is found in rocks that are altered by the directed pressure of a convergent plate boundary. Recrystallization is what marks the separation between limestone and marble.

Marble that has been exposed to low levels of metamorphism will have very small calcite crystals. The crystals become larger as the level of metamorphism progresses. Clay minerals within the marble will alter to micas and more complex silicate structures as the level of metamorphism increases. Marble Dimension Stone: Marble cut into blocks and slabs of specific size is known as "dimension stone." Photo © iStockphoto / Thomas Lehmann. Physical Properties and Uses of Marble Marble occurs in large deposits that can be hundreds of feet thick and geographically extensive. This allows it to be economically mined on a large scale, with some mines and quarries producing millions of tons per year. Most marble is made into either crushed stone or dimension stone. Crushed stone is used as an aggregate in highways, railroad beds, building foundations, and other types of construction. Dimension stone is produced by sawing marble into pieces of specific dimensions. These are used in monuments, buildings, sculptures, paving and other projects. We have an article about " the uses of marble " that includes photos and descriptions of marble in many types of uses. Gray Marble: This specimen has calcite cleavage faces up to several millimeters in size that are reflecting light.

The specimen is about two inches (five centimeters) across. Calcium carbonate medicines: Marble is composed of calcium carbonate. That makes it very effective at neutralizing acids. Highest purity marble is often crushed to a powder, processed to remove impurities, and then used to make products such as Tums and Alka-Seltzer that are used for the treatment of acid indigestion. Crushed marble is also used to reduce the acid content of soils, the acid levels of streams, and as an acid-neutralizing material in the chemical industry. Photo © iStockphoto / NoDerog. Rock & Mineral Kits: Get a rock, mineral, or fossil kit to learn more about Earth materials. The best way to learn about rocks is to have specimens available for testing and examination. Color: Marble is usually a light-colored rock. When it is formed from a limestone with very few impurities, it will be white in color. Marble that contains impurities such as clay minerals, iron oxides, or bituminous material can be bluish, gray, pink, yellow, or black in color. Marble of extremely high purity with a bright white color is very useful.

It is often mined, crushed to a powder, and then processed to remove as many impurities as possible. The resulting product is called "whiting." This powder is used as a coloring agent and filler in paint, whitewash, putty, plastic, grout, cosmetics, paper, and other manufactured products. Acid Reaction: Being composed of calcium carbonate, marble will react in contact with many acids, neutralizing the acid. It is one of the most effective acid neutralization materials. Marble is often crushed and used for acid neutralization in streams, lakes, and soils. It is used for acid neutralization in the chemical industry as well. Pharmaceutical antacid medicines such as "Tums" contain calcium carbonate, which is sometimes made from powdered marble. These medicines are helpful to people who suffer from acid reflux or acid indigestion. Powdered marble is used as an inert filler in other pills. Hardness: Being composed of calcite, marble has a hardness of three on the Mohs hardness scale . As a result, marble is easy to carve, and that makes it useful for producing sculptures and ornamental objects. The translucence of marble makes it especially attractive for many types of sculptures.

The low hardness and solubility of marble allows it to be used as a calcium additive in animal feeds. Calcium additives are especially important for dairy cows and egg-producing chickens. It is also used as a low-hardness abrasive for scrubbing bathroom and kitchen fixtures. Ability to Accept a Polish: After being sanded with progressively finer abrasives, marble can be polished to a high luster. This allows attractive pieces of marble to be cut, polished, and used as floor tiles, architectural panels, facing stone, window sills, stair treads, columns, and many other pieces of decorative stone. Another Definition of Marble The name "marble" is used in a different way in the dimension stone trade. Any crystalline carbonate rock that has an ability to accept a polish is called "marble." The name is sometimes used for other soft rocks such as travertine, verd antique, serpentine , and some limestones. Natural Stone FAQ | M S International, Inc. | Premium Natural Stones What is Natural Stone? "Natural Stone" refers to a number of products quarried from the earth, used over many thousands of years as building materials and decorative enhancements.

These products include Granite, Marble , Limestone , Travertine , Slate , Quartzite, Sandstone, Adoquin, Onyx, and others. They are more than just rocks – natural stone is hand selected from the best, most consistent sources for durability and beauty. Natural stone products differ in composition, color, and texture even among pieces from the same source. This is usually considered a benefit, lending itself to one of a kind designs and distinctive, dramatic applications. Who needs natural stone in the USA ? In past eras, Natural Stone has mainly been used for large-scale construction and in formal applications such as churches and government buildings. It has also been used for road construction and monuments. For residential construction, wood and brick have been the traditional choice. However, there has been a growing trend in recent years to use Natural Stone in residential construction for both structural and decorative use. Popular applications include entryways, atriums, bathrooms, fireplaces, floors, countertops, and many other surfaces. Why should I use natural stone in my home? Natural stone is prized its distinctive beauty and the sense of peaceful tranquility it creates, but there are also many practical benefits to using Natural Stone in your home.

Natural Stone products are more durable than many artificial products, often lasting for decades with very little maintenance. With Natural Stone there are no worries about exposure to harmful chemicals in the home or released into the environment during production or disposal. Why invest time and money into a look-alike? Natural Stone is the real thing that the artificial products try to emulate. Natural Stone products include Granite , Marble , Limestone , Travertine , Slate , Quartzite , Sandstone and Onyx . Granite For maintenance-free elegance and durability, granite is unmatched. Its incredible strength and density makes granite the perfect choice for massive structural work – walls, monuments and supports. Though it is the hardest of structural stones, the amazing variety of mineral-rich colors and natural patterns gives it ornamental value as well. Granite products are ideal for flooring, countertops , vanities and decorative exterior applications. Marble Prized for its timeless style, texture and high-gloss polish along with a rich palette of beautiful colors, marble has a place anywhere in the home. Available in solids or dramatic veined varieties, marble may be carved or sculpted in many ways, making it one of the most versatile decorative stones.

Often seen as a symbol of luxury, modern technology brings beautiful marble products even to budget-conscious homeowners. Serpentine Marble Also referred to as Verde Antique, Serpentine Marble is a dramatic green color with strong white veining. Slate Formed over thousands of years of sedimentary deposit and compression, slate splits naturally into beautifully textured layers. The various shades of slate products – brown, yellow, dark gray, pink, lavender and more – may even occur within the same piece of stone. Durable and stain-resistant, slate products are often used for flooring, cladding and landscaping . Quartz Shimmering and sparkling with tiny quartz crystals, Quartz is a rock similar to slate with a medium grained texture and incredible durability. Differing mineral content creates many color variations, from the sedate white, gray or beige to more adventurous shades of purple and pink. Quartzite is widely used for wall veneers and decorative tiles. A naturally non-skid texture makes it a perfect candidate for flooring indoors and out, including areas with heavy traffic and exposure to the elements.

Sandstone With a uniform texture, an appealing variety of colors and finishes, and weather resistant durability, it's easy to see why sandstone products have been used for thousands of years for walls, floors, and pavers. As with other types of rock, its variations result from differing mineral composition – there's a sandstone product to match any décor. Limestone The muted, soft tones of limestone are perfect for today's casual and comfortable lifestyles. Available in hues of soft beige and tan, either polished or honed, limestone products are ideal for bathrooms, fireplaces, countertops and flooring in low-traffic, informal areas. Travertine Valued for its banded, pitted “distressed” appearance, travertine adds rich, distinctive character to a variety of indoor and outdoor building projects. Its patterns and veining effects were formed by hot spring water percolating through underground limestone. When used for interior applications, travertine is often filled with cement, grout or resin and sealed to create a smooth, stain-resistant surface. Shell Stone Shell Stone is a sedimentary stone similar to limestone , with many small shells embedded and visible upon its surface.

Onyx A translucent stone with a glossy, polished surface, onyx is composed of crystalline silica and closely related to agate, a semi-precious stone. Often found in caves, onyx is formed by the slow flow of cold, carbonated spring water. Onyx is available in pastel shades of yellow, brown, green, orange, and white. Cantera Stone Cantera is a sedimentary stone that comes from the riverbeds of Mexico. It is used extensively for architectural columns, moldings, and for pavement tiles. How do natural stone tiles differ from ceramic tiles? The most important difference is this – Natural Stone is a product of nature, and Ceramics are man-made. Most man-made materials cannot compare in durability to natural ones. While damaged ceramic tiles usually need replacing, natural stone usually needs minimal restoration if stained or scratched. Other differences are explained below: CERAMIC Why is granite preferred for kitchen/bar countertops? Countertops in kitchens and bar areas are often exposed to acidic substances such as lemon, vinegar, alcohol, and tomato sauce. Knives, dishes, pots and pans, and other implements may cause scratching of lesser materials.

Granite is the hardest and densest of all natural stones – the feldspar content keeps it water resistant, and the silicates it contains won't react with acid. These properties help Granite resist staining and retain its fine luster over a longer period of time than ceramic tiles or other stones. Although Marble is commonly requested for countertops in bars and kitchens, marble's high carbonate content makes it vulnerable to acidic substances. Why are limestones and travertines preferred for family or living rooms? The family or living room in a home is a place for peace and relaxation, and the soft, muted tones and textures of limestone or travertine are the perfect touch. Available in shades of beige, tan, yellow and gold and processed with a tumbled or antiqued texture, limestone complements all types of furniture and upholstery. Why is marble preferred for bathrooms and fireplaces? Homeowners often enjoy bathrooms with bold colors and smooth, flowing patterns. Marble is the perfect choice for this application due to its wide spectrum of available colors. It also lends itself well to carved patterns and details, creating both traditional and artistic designs.

While kitchen countertops are often exposed to acidic substances, bathroom countertops are more likely to be exposed to alkaline products, which do not react with Marble. Why is slate preferred for patios or atriums? The earth tones and rustic look of slate create a comfortable, natural look that is right at home with exterior landscaping and interior garden designs. Slate is naturally slip resistant, even when wet, and is much less likely to show dust and dirt than polished granite or marble. It's also relatively low priced, which makes it a great choice for large, informal areas. Why are most natural stones imported? Sources of natural stone with desirable qualities are found all over the world, in many different locations. Some sources are better than others due to the stones' appearance, hardness, and other qualities. Therefore, stone may be quarried in China, India, Africa, South America, and some does come from within United States borders. Cost of processing is also a factor. Since natural stone has been used as a building material for thousands of years in many locations overseas, those areas have a long-established system for quarrying and processing these stones which is efficient and economical. What is the quality difference in stone from different countries?

Natural stone from different areas contains a varying mix of mineral deposits and rock formations. For example, the mineral Mica may be found more frequently in some areas, which means that the rock from that location will contain bigger shiny crystals than we would find in places where less Mica is found. Some countries quarry more limestone than granite . Therefore, stone from certain places may be better suited for one application than another. Natural stone qualities and characteristics differ due to geological formations, not geographical boundaries. Why can some stones not be used for exterior applications? Some types of stone are better suited for interior applications than exterior because they cannot withstand harsh weather extremes and may crack, crumble, or fade. Also, stones with naturally slip-resistant surfaces are better for outdoor walkways or patios than those with smooth, polished surfaces. Some multicolored slates bleed color upon contact with water. Granite tiles and slabs for commercial and residential applications do not emit harmful radiation. For more information, consult the Marble Institute of America's website. Cost of Stone Why are some stones more expensive than others? Stones that are harder and denser are more difficult and expensive to quarry and process.

Quarrying methods vary as well; stones may be quarried below ground, which is more expensive than above ground. Also, since natural stone is quarried all over the world, long distance shipping factors into the price. Do I get lower prices for larger quantity? The availability of a particular stone is the most important factor in determining price. However, handling and transportation cost does drop slightly for a larger quantity. The best way to reduce cost is to find a stone dealer who is running a special on a particular product. Stone Finishes The different types of stone finishes include: Natural Cleft Unique to slate , it has a slightly uneven surface that is still usable for flooring. This finish cannot be created, but occurs naturally as the layers of slate are quarried. One side (back side) can be gauged to facilitate ease of “thin set” installation. Some marbles, sandstones and limestones are available with heavy clefting, suitable for wall installations only. Polished Grinding, sanding, and buffing produces a high gloss, mirror-like surface. Honed Grinding and sanding produces a smooth, yet not glossy finish. This is best for low maintenance, high traffic applications.

Flamed A flamed surface is achieved by subjecting the stone to the high temperature flame of a torch and burning most of the carbon content, leaving textured quartzites with gentle coloration. Sandblasted This is a rough, but tidy look created by applying a high pressure blast of sand to the stone’s surface. River Wash This finish is often given to granites, and provides a non-slippery surface while retaining the coloration and grain structure of the stone. Leather Available only in Melange marble, this finish gives the stone a suede look and feel. This texture is smooth and slip-resistant. Tumbled Tumbling stones in a solution of sand, water and mild acid creates an old world, weathered look. Split Face Mainly used for cladding, this is achieved by splitting stone either by hand or by machine so that the surface exhibits a natural quarry texture. It has a flat back and uneven front surface, and creates the uneven look of protruding bricks. Fleuri Cut This is achieved by cutting quarried marble or stone parallel to the natural bedding plane. Cross-Cut The cross-cut method involves end-cutting blocks of travertine to display a less linear, more rounded “wavy” pattern.

Vein Cut Opposite of cross-cutting, the veining of the stone is shown as a linear pattern. Veneer Stone Any stone used as a decorative facing material as wall cladding which is not meant to be load-bearing. Veneer may be made from different finishes, such as split face, cleft, honed, polished, flamed or tumbled. Gauged vs. Ungauged Slate is cleft out of blocks to form tiles. When it is cleft by machine or saw, it is gauged because a uniform thickness is formed. Ungauged stone is hand-cleft and its thickness may vary up to 5/8 of an inch. There are three important reasons for choosing one finish over another in certain applications: Safety When choosing flooring, it's important to choose a slip-resistant surface for outdoor applications where the floor may become wet. Highly polished surfaces should only be used for interior floors. Also, highly clefted, uneven surfaces may cause a tripping hazard when used for flooring. Maintenance Softer, less dense stones such as marble or limestone are unsuitable for high traffic areas because they will quickly become dull and will need frequent restoration to maintain their finish.

Usability The application should be consistent with the type of finish selected. A rough finish such as flamed would be a poor choice for countertops, due to the difficulty in cleaning it. Clefted material should not be used for tabletops, because it would present an uneven surface. Is a polished floor recommended for a commercial application? Polished flooring may be used in a commercial application if the floor is unlikely to become wet and slippery. It is advisable to have the floor material professionally tested prior to installation. Sealers are available that can improve the slip resistance of the surface without removing its gloss. Why are travertines filled or unfilled? Travertine is characterized by the presence of many tiny holes, caused by trapped gas bubbles during its formation. This creates a porous, uneven surface, which is referred to as Unfilled Travertine. When these cavities are filled with cement or another material, the result is called Filled Travertine and may be honed and polished to provide a uniform surface similar to marble. Is cleft finished slate a tripping hazard? Slate with a heavily cleft finish may create a tripping hazard. Most slates are lightly clefted and suitable for flooring in kitchens, bathrooms and on patios.

A pallet of slate may contain a few pieces with heavy clefting, but these are generally not used for the flooring installation. What is thermal or flame finish? The thermal, or flamed finish is achieved by subjecting the stone to the high-temperature flame of a torch. This burns off most of the carbon content, creating textured quartzites with gentle coloration. Only granite is tough enough to withstand this treatment, and the piece must be fairly thick or it may crack or break under heat and pressure. This is a popular finish for commercial wall and flooring applications. What is stone tumbling? Tumbling stones in a solution of sand, water and mild acid creates an old world, weathered look. Typically sizes of 5/8" X 5/8" to 6"X 6" and sometimes even 8"X 8" are true tumbled pieces. Larger sizes are given a "Tumbled" finish, manually. Very small pieces like 5/8" X 5/8" & 1" X 1" are usually, mounted on 12" X 12" meshes for ease of installation.

Most commonly used size is 4" X 4" and it is used in straight & diamond patterns, or as accent pieces. When mixing different size tumbled pieces, the look may vary. Is the sizing always exact in tumbled material? Tumbled stone pieces are intended to produce a rustic, old-world look. Therefore, they are not created with precision and may vary slightly in size. Some pieces may have large chips on the edges or may have a corner missing. Care must be taken to ensure an even surface when installing tumbled stone flooring. Stone Installation Can I specify that there be no grout joints? Creating an installation without visible grout joints is difficult, but if the surface of the floor is straight and the tiles are perfectly cut, very little grout should be seen. A professional, experienced installer should be chosen to create this look. Who determines grout color? Grout is an important design element. Because it is used to fill the spaces between each tile, the grout must be selected carefully. A wide variety of grout colors is available to enhance the beauty of the tile installation and may be chosen to contrast with, match, or accent the tile. Contrast Grout: emphasizes a pattern created by the tile.

Matching Grout: blends seamlessly with the tile. Accent Grout: a shade slightly different from the tile, gives them an appearance of depth. Can marble tile be installed on wood surfaces? No. It is not recommended that marble tiles be installed directly on wood flooring or any other flooring that moves. The movement can cause tile to crack. The best solution is to have cement board installed by a professional installer over the surface to be tiled. Can I specify the exact stone color I want? Granite , marble , and slate may be available in nearly any color, so it may be possible to specify stone color, with some tolerance for shade differences. Not all stones are available in all colors, however. Travertines, for example, are only found in shades of beige, yellow, and gold. The criteria for selecting stone color will depend on the application. Color choice can make a room appear larger or smaller, formal or warm and inviting. Consider the following characteristics: Lighter colors tend to make a smaller room seem larger. Dark colors tend to make a room more intimate and cozy. Solid colors, smooth and polished tiles show more dirt and require more maintenance. Patterned material, usually in a honed finish, is one of the easiest to maintain.

Dramatic patterns can help highlight and accent portions of the room, including architectural features. How much variation can I expect from the sample of stone shown? Each stone is unique, and some types of stone display more variation between the pieces than others. Granites show little variation in color, but may have differing patterns and grain density. Slates tend to show a wide variation in color, even within the same pallet of stone. How can I enhance the color of travertine? Adding depth and shine to travertine tiles can be accomplished through the application of enhancing sealers made specifically for travertine tile. Enhancing sealers are available at most home improvement and hardware stores. How can I fill the natural voids and holes in travertine tile if I want a smoother surface? Part of the beauty of travertine tilles, is the natural composition causes small voids and holes. If however, you want a smoother surface, the best way to fill the holes is to use a sanded grout in a color as close to the travertine as possible. Types of Stones :: Suraj Mining (Granite) Pvt. Ltd., INDIA Infrastructure | Quality | Why Choose Us?

| FAQs | Shipping & Logistics Types of Stones Natural stones are classified according to their mineral content and the process of their formation. Most of these minerals can be identified by their color, hardness and crystal formation. However, a wide array of minerals are often difficult to identify. Many stones look similar to each other, but are actually different. Good stones are characterized by durability, hardness, strength, amenability to dressing, appearance, weight, fineness of grain, compactness, porosity and absorption. In order to be suitable as building stones, a rock should have specific qualities such as capacity to stand the ravages of time and weather, requisite strength to bear strain and super-incumbent weight, attractive colour and general appearance. Its structure must also be such as to allow quarrying into good sized blocks or planes. India possesses extensive deposits of different kinds of building and monumental stones. It is one of the few major countries known for the production and export of natural building stones of various colours. The most important building stones in India are the granites/and allied rocks, sandstone, limestone, slate and marble. The different types of stones are: I. Sedimentary Stones These stones came from organic elements such as glaciers, rivers, oceans, and plants.

Tiny sedimentary pieces broke off form these elements and accumulated to form rock beds. They were bonded through millions of years of heat and pressure. Major types of sedimentary stones are: Limestone Mainly consisting of calcite, it does not show much graining or crystalline structure. It has a smooth granular surface and varies in hardness. Some dense limestone can be polished and is more likely to stain than marble. Common colors are black, grey, white, yellow or brown. Limestone is known to contain lime from sea water, and that's why the nomenclature. Sandstone Sandstone is a sedimentary stone that is typically the result of quartzite stone being eroded and redeposited by either wind or water. Sandstone mostly consists of quartz, silica, iron oxide and calcium carbonate and are durable, weather, acid and thermal resistant and have crushing strength. Sandstones are most highly craftable and manageable, they can at most take a honed polish, and are used as garden and commercial landscapes, exterior wall claddings, panels, pillars, sculptures, arches,etc. They come in an array of colors & shades and can be chiseled and dressed to a smooth surface in various attractive shapes.

Soapstone It is a very soft stone made of a variety of talc. It is a dense mineral that wears well and is often resistant to oxide. Travertine Usually it has a cream or reddish color and is formed through the accumulation of calcite from hot springs. It contains lots of holes that were formed from water flowing through the stone. These holes are often filled with synthetic resins or cements and requires lots of maintenance if the holes are not filled. II. Metamorphic Stones These stones originates as a result of natural change from one type of stone to another type by the mixed action of heat, pressure and minerals. The change may be a development of a crystalline formation, a texture change, or a color change. Marble The term "Marble" is derived from the Latin word "Marmar" which itself comes from the Greek root "Marmarous" meaning thereby a shining stone. Marble is a metamorphic rock resulting from the re-crystallization of limestone softened from heat and pressure. Main constituents are calcium and dolomite. Hardness ranges from 2.5 to 5 on the MOH scale. Marble is usually heavily veined and shows lots of grains.

Dimensional marble specifications include smooth textures, ease in crafting sculptures, hence highly manageable. It is a reasonably strong and durable stone. It takes good polish, popularly used as wall claddings, floors, skirtings, table tops, treads and risers, sculptures, artifacts, etc. Marble is classified into three categories: Dolomite: If it has more than 40% magnesium carbonate. Magnesium: If it has between 5% and 40% magnesium. Calcite: If it has less than 5% magnesium carbonate. Slate Slate is a very fine grained metamorphic rock derived from the sedimentary rock 'shale'. Slate is composed mostly of mica, chlorite and quartz. Characteristically, the rock may slit into relatively thinner slabs and can break easily. Some slates take very good polish, are extremely beautiful and more cost effective than most other wall and floor coverings. Slate has a fine to medium grained surface texture. It renders a very graceful, natural finish to any building or home. Serpentine It is identified by its marks, which look like the skin of a serpent.

Hardness rates from 2.5 to 4 on the MOH scale and most popular colors are green and brown. Contains lots of magnesium, and has an igneous origin. It does not always react well to recrystallization or diamond polishing. III. Igneous Stones These rocks are mainly formed through volcanic material such as magma. Underneath the earth's surface, liquid magma cooled and solidified. Mineral gases and liquids penetrated into the stone and created new crystalline formations with various colors. Granite The term "Granite" is derived from the Latin word "Granum" meaning "grain" because of its granular nature. Granite is an Igneous Stone, primarily made of Quartz(35%), Feldspar(45%) & Potassium. Dimensional granite specifications include high load bearing capacity, amenability to cutting without secondary flaws, ability to yield thin and large slabs and - above all - durability. Granite is a very strong and durable stone. It takes heavy gloss polish, popularly used as architectural stone for interior and exterior walls, floors and monumental stone. IV. Man Made Stones These stones are derived from unnatural mixtures such resin or cement with the additive of stone chips.

Terrazzo Natural Countertop Geology and Stone Identification Natural Countertop Geology and Stone Identification Posted on June 13, 2016 11:54:32 AM Those in the stone industry, and those interested in stone, should be familiar with basic geology. As a doctor studies the systems of the human body to prescribe treatments and remedies, you should also be familiar with the formations and changes of stone. The study of these changes is known as geology. Why is geology so important? There are many reasons. Granite and marble, for example, differ greatly in their hardness. A hard material such as granite may require harder abrasives for refinishing. Certain limestones contain very sharp minerals that can quickly damage a polishing pad or set of diamond abrasives. You need to know which stones these are. The following is designed to provide you with a basic introduction to geology. In order to understand the problems you may encounter with stone, it is important that you understand the formations and changes that occur with stone. A thorough understanding will make your job much easier. Stone Types It is believed there are somewhere near 9,000 different varieties of stone.

Of course it would be impossible for anyone to know every stone, but all stone can be classified into three distinct groups. Learning these three types and their characteristics can solve most of the problems you may face. For example: Granite, which is an igneous rock, contains quartz, which is very hard. For this reason, the proper abrasive must be chosen for finishing. Marble, which is a metamorphic rock, contains calcium carbonate that reacts to acid. This knowledge would tell you that acidic cleaners would damage most polished marble surfaces. Travertine, a sedimentary stone, consists of small grains of minerals bonded to each other with softer minerals. The minerals are very coarse and can rapidly damage a diamond abrasive. The following are the three classifications of stone and how to identify them. Igneous Rocks (Granite) Igneous rocks are formed from the solidification of magma deep in the earth. They contain 45 to 66 percent silica (quartz). The remaining minerals are mostly feldspar, mica and iron ores. Granite is the most abundant igneous rock found on Earth. Characteristics of Igneous Rocks Rocks exhibit a crystalline form with grain size ranging from very small to several inches.

The large crystal granites are formed when the magma cools slowly. The smaller crystals are formed with rapid cooling. All this takes place before the magma reaches the Earth’s surface. If it does reach the surface, it’s called lava. Hardness ranges from six and higher on the Mohs’ scale (see Figure 1). Igneous rocks can be identified very easily by performing a scratch test with an ordinary knife blade. If it is difficult to scratch, it is most likely igneous. Igneous rocks will generally not react with acids. However Hydrofluoric Acid (HF) will react with a polished surface. Many stone cleaners designed for sandstone contain HF. Make sure to read product labels and material safety data sheets when using any stone cleaner or chemical. Avoid using HF on all stones if possible. The minerals contained in igneous rocks are usually dense and packed tightly. They lack bedding or foliation. However, be aware of a granite look-a-like known as gneiss. Gneiss looks like an igneous rock but is a transitional material between metamorphic and igneous. It is a brittle material and does have a bedding plane. Color key for igneous rocks: White granites are rich in potassium.

Combinations of mica and quartz result in gray. Pink contains sodium and calcium rich feldspar. Sedimentary Rocks (Limestones and Sandstones) Sedimentary rocks are produced from erosion of other rocks, compression and underground water erosion. The sedimentary rocks cover nearly 75 percent of the Earth’s surface. For our purposes, sedimentary rocks can be classified into two types: limestones and sandstones. Limestones are formed in shallow waters of the sea shelf. They consist of calcite, but maybe mixed with other minerals depending on the water clarity when it was formed. Many limestones contain a mineral known as magnesium carbonate (dolomite). Dolomite does not react with acid unless it is first crushed. Any rock with more than 50 percent carbonate mineral is classified as a limestone. Some common limestones are travertine, slate, coral, shell stone or coquina. Limestones have a bedding plane, and because they are formed in the sea, they often contain fossils and shell fragments that make them more easily identifiable. Sandstones are also sedimentary rocks that are primarily quartz minerals loosely cemented together with calcite, iron oxides and/or mud.

Sandstones are frequently used as a dimensional building stone. Major cities throughout the world contain buildings made with sandstone. Some common sandstone is brown stone and shale. Sandstone can be recognized by its distinct sand-like appearance. It fractures very easily around the individual grains, and exhibits a distinct bedding plane. Metamorphic Rocks (Marble And Slate) Metamorphic rocks are limestones that have been exposed to high temperature and pressure over a long period of time. This change is known as metamorphoses and causes the minerals to go through a molten phase. For this reason, most marbles have distinct veins, swirls or bands, but there are exceptions. Light veins may contain quartz and feldspar, while dark veins may contain hornblend or biotite. All marbles will have calcite and/or dolomite and will react with acid. Mineral Identification In order to identify the types of stone you may encounter, you need to be able to identify the minerals in the rocks. Certain groups of rocks contain specific types of minerals. We know granites are igneous and contain quartz, marble is metamorphic and contains calcite, and sedimentary materials such as limestone can contain dolomite.

The minerals contained in the stones we deal with have some physical and chemical properties. Some of these properties can be tested and will tell us which mineral we are dealing with. The following are those properties: Luster — Luster is the way a mineral reflects light from its surface. A mineral can be metallic, which means it looks shiny, or nonmetallic, which has no shiny reflection but is described as glassy or vitreous, pearly, silky, dull, greasy or soapy. Hardness — Frederick Mobs in 1822 developed the hardness test which measures how resistant a mineral is to abrasion. We commonly call this the “scratch test.” Taking minerals and scratching one against the other developed the test. The one that scratched was softer then the one that caused the scratch. This test was continued until 10 minerals were discovered. The minerals were arranged in order of hardness and given a number. “1” was the softest and “10” was the hardest. Cleavage — Cleavage is how the mineral breaks or fractures. Some minerals, when they break, will have one, two or three cleavages.

This is perhaps the hardest property to determine and will require the use of a field microscope or hand lens. Color — Color is an important clue to identifying certain minerals. Stone gets its color from many of these minerals. Some minerals only need to be present in very small amounts to lend color to a stone. For example, many of the red granites and marbles are the result of the mineral iron. Acid Test — The acid test is an important test and can immediately tell you if you are dealing with a calcium-based stone. A simple drop of a dilute solution of hydrochloric acid will tell you if you have marble, limestone or granite. If the acid bubbles and/or fizzes, you have calcium. No reaction means there is no calcium and you may have granite or possibly a dolomitic limestone. Those are the most common properties used to identify a mineral. Geologists and others may also use specific gravity; magnetism, electrical properties, optics and taste for further identification. Other Stone Types Marble, granite and limestone are the most common interior stone types that you will encounter. However, there are others. The following is a brief explanation of those types: Slate – Slate can be found both indoors and our.

It is a stone that has been metamorphosed from shale and consists of clay-like materials. It can be recognized by its sheet-like appearance and is found in earth-tone colors. Slate will rarely have a high polish unless a coating is placed on it. Slate can be a problem for the architect/designer. It contains high clay content, so it will often flake, spall and develop efflorescence easily. This is especially true in wet areas. Slate is best treated with a good quality silicone penetrating sealer . Sandstone – Sandstone is a sedimentary material, which consists of sand crystals cemented together with natural clays. It is seldom seen as flooring material, but an architect or designer will run across a floor or two. Sandstone is very rough because of its sandy structure and is very abrasive on diamond discs. It is acid-resistant and rarely polished. Sandstone is very porous and should be sealed with a penetrating sealer . Quartzite – Quartzite is also a rare flooring material but is gaining in popularity. It is metamorphosed quartz sand and is classified as sandstone, exhibiting those properties. Shell Stone or Coquina – Shell stone or Coquina is a limestone composed of broken fragments of shell and coral.

It is a porous sedimentary material and is easily identified by its shell or coral fragments. It should not be resurfaced because it is very abrasive stone and will tear diamond discs. Flagstone/Blue Stone – Flagstone is a term given to almost all material cut into thin, irregular shapes. Found extensively on sidewalks, foyer entrances and pool decks, flagstone can be almost any stone material but is commonly the sandstone type known as blue stone. Blue stone gets its name from its distinct blue color. Flagstone should not be ground and should only be cleaned and sealed. Onyx – Onyx is a type of marble, which has been formed by the deposits of cold solutions. It is a translucent material with veins running concentrically to one another. It is very expensive and can be found on table-tops and small pieces of furniture. It can be treated just like marble and takes a high shine. Soapstone – Soapstone is one of the softest materials composed of talc. For this reason it makes an excellent carving material and can be found on fireplace surrounds and hearths. It is treated like marble and should be sealed. Travertine – Travertine is a limestone formed in hot springs.

Water movement causes the erosion of the stone, creating numerous holes of varying sizes. A polished travertine will have its holes filled with a color-matched Portland cement fill. These fillers do not take a high polish and therefore the overall polish is blotchy. Article courtesy of StoneForensics.com Uses of Marble in Architecture, Sculpture, Design, and More Home » Rocks » Metamorphic Rocks » Uses of Marble The Many Uses of Marble From monuments to crushed stone to cosmetics and pharmaceuticals, very few rocks have as many uses as marble. Taj Mahal The Taj Mahal is one of the most beautiful and famous buildings in the world. It was built between 1632 and 1653 as a mausoleum for Mumtaz Mahal, the third wife of Mughal emperor Shah Jahan. Marble was used extensively throughout the building, including the marble domes and towers. Photo © iStockphoto / standby. The Properties of Marble and Its Uses Very few rocks have as many uses as marble . It is used for its beauty in architecture and sculpture. It is used for its chemical properties in pharmaceuticals and agriculture. It is used for its optical properties in cosmetics, paint, and paper.

It is used because it is an abundant, low-cost commodity in crushed stone prepared for construction projects. Marble has many unique properties that make it a valuable rock in many different industries. The photographs and captions below illustrate just a few of its varied uses. Many Colors of Marble Marble occurs in a very wide range of colors. Marble formed from the purest limestones is white in color. Iron oxide impurities in the limestone will produce a yellow, orange, pink or red color. Clay minerals can produce gray colors that often occur in bands after the compositional stratification of the original limestone. Abundant bituminous materials can produce dark gray to black marble. Marble that contains serpentine often has a green color. Photo © iStockphoto / Tina Lorien. Supreme Court Building The Supreme Court building was constructed between 1932 and 1935 using several different types of marble. Vermont marble was used extensively in the exterior. The inner courtyards were made using bright white marble from Georgia, and the interior corridors and entrance halls are made from creamy white marble from Alabama. Photo © iStockphoto / GBlakeley.

Washington Monument The Washington Monument was built of marble between 1848 and 1884. Initial work on the structure was done using marble from a quarry located near Texas, Maryland. The project was then delayed for nearly 30 years due to a lack of funds. When construction resumed in 1876, similar stone from the Texas quarry was not available, so stone from the Sheffield quarry near Sheffield, Massachusetts was used. The Sheffield quarry had problems delivering stone in a timely manner, and in 1880 their contract was cancelled. A new contract then went to the Cockeysville Quarry near Baltimore, Maryland which supplied a slightly darker dolomitic marble. These different stone sources can be seen in the monument as labeled in the photo above. Photo and annotation by the United States Geological Survey. Marble Stair Treads, Risers, Floor Tile Marble is a material used in prestige architecture and interior design. This photo shows stair treads and risers made from brecciated marble and floor tiles made from marble in a variety of colors. Photo © iStockphoto / Nikada.

Bust of Artemis Marble is a translucent stone that allows light to enter and produce a soft "glow." It also has the ability to take a very high polish. These properties make it a beautiful stone for producing sculptures. It is soft, making it easy to sculpt, and when it is fine-grained it has uniform properties in all directions. Some of the world's most famous sculptures have been produced from marble. This bust of the Greek goddess, Artemis, is a copy of an original Greek work. Photo © iStockphoto / Diane Diederich. Lincoln Memorial The Lincoln Memorial was built between 1914 and 1922. Many different stones were used in the memorial. The terrace walls and lower steps were made of granite from Massachusetts. The upper steps, columns, and outside facade were made using marble from Colorado. The interior walls are Indiana limestone (called "Indiana Marble" by many architects). The floor was made using pink marble from Tennessee, and the statue of Lincoln is made from a very bright white marble from Georgia. Each type of stone was selected for its properties along with an effort to utilize stone from many parts of the United States. Photo © iStockphoto / ntn.

Cemetery Markers Marble is often used as a cemetery marker. It is a very attractive stone. It is economical because it is relatively easy to cut and engrave. In comparison to rocks like granite , it is not as resistant to acid precipitation and tends to lose edges and detail over time. Photo © iStockphoto / JPecha. Whiting Marble of exceptionally white color is sometimes used to produce a product known as "whiting," a white powder that is used as a pigment, brightener, and filler in paint, paper and other products. Photo © iStockphoto / nsilcock. Cutting Marble A large-diameter diamond saw cuts a block of marble into dimension stone at a factory. Slabs and blocks of marble are used for stair treads, floor tiles, facing stone, cemetery stones, window sills, ashlars, sculptures, benches, paving stones and many other uses. Photo © iStockphoto / maskpro. Agricultural Lime Some marble is heated in a kiln to drive off the carbon dioxide that is contained within the calcite. What remains after kiln treatment is the calcium oxide - known as "lime." Lime is used as an agricultural soil treatment to reduce the acidity in soil.

When applied in combination with fertilizer, it can increase the yield of a soil. This test plot shows a portion of a corn field where no lime and no fertilizer were applied. The plants in that plot are struggling to survive. Photo by the Agricultural Research Service, United States Department of Agriculture. Marble Dimension Stone Marble cut into blocks and slabs of specific size is known as "dimension stone." Photo © iStockphoto / Thomas Lehmann. Marble Quarry Equipment working in a marble quarry near Madrid, Spain. In this quarry the marble is being sawn into blocks for the production of dimension stone. Photo © iStockphoto / vallefrias. Acid Neutralization Marble is composed of calcium carbonate. That makes it very effective at neutralizing acids. Highest purity marble is often crushed to a powder, processed to remove impurities and then used to make products such as Tums and Alka-Seltzer that are used for the treatment of acid indigestion. Crushed marble is also used to reduce the acid content of soils, the acid levels of streams, and as an acid-neutralizing material in the chemical industry. Photo © iStockphoto / NoDerog.

Crushed Stone - Construction Aggregate Some marble is mined, crushed, sized and sold as a construction aggregate. It can be used as fill, subbase, landscape stone and other uses where soundness and abrasion resistance are not critical. Because marble is composed of calcite , it cleaves more readily than limestone and does not have the strength, soundness, and abrasion resistance of granite and other more competent rocks. Photo © iStockphoto / AdShooter. Soft Abrasive Marble is composed of calcite, a mineral with a Mohs hardness of three. It is softer than most bathroom and kitchen surfaces and can be used on them as a scrubbing agent without producing scratches or other damage. Calcium Feed Supplement Dairy cows and chickens need a steady supply of calcium to produce milk and eggs. Farms that raise these animals often use animal feeds that have been supplemented with additional calcium. Powdered limestone and marble are used to produce these supplements because they are softer than the animal's teeth, soluble, and rich in calcium. Photo © iStockphoto / NiDerLander.

More Rocks Marble: Characteristics, Uses And Problems Marble: Characteristics, Uses And Problems Procedure code: Outdoor Sculpture Manual - Center For Public Buildings Division: Last Modified: 08/02/2016 This standard includes general information on the characteristics and common uses of marble and identifies typical problems associated with the material. See 04400-01-S for guidance on inspecting stone masonry failures. Introduction Marble is an extremely hard, metamorphic stone composed of calcite (CaCO3). It is formed as a result of the recrystallization of limestone under the intense pressure and heat of geologic processes. The effect of this process is the creation of a stone with a very tight crystalline structure and small but definite porosity. Because of its structure, marble can take a very high polish and is a very popular decorative stone for architectural and sculptural uses. The limited porosity of marble, especially polished marble, makes it less vulnerable to the leaching effects of water. Calcium carbonate, however, of which marble is composed, is highly susceptible to attack by acidic agents.

Marble is readily dissolved by acids, even very dilute acids, however the actual results of acidic exposure will vary with the nature of the acid. Chlorides, nitrates, sulfates and other chemical compounds react differently with marble and produce various by-products, which have a wide range of solubility and impact on the durability of marble. For this reason, it is always important to determine the exact type of pollutants causing marble deterioration. Marble itself can be of two types, one composed of calcite and the other of dolomite. Dolomitic marble is much more resistant to acid attack than calcite marble. The color of marble ranges from the brilliant white of calcite to black, including blue-gray, red, yellow and green, depending upon the mineral composition. Typical uses Marble has many decorative and structural uses. It is used for outdoor sculpture as well as for sculpture bases; in architecture it is used in exterior walls and veneers, flooring, decorative features, stairways and walkways. The way in which the stone is used may be a factor in limiting or controlling the severity of exposure.

The use or function of the marble may also affect the feasibility of applying certain treatments, but type of use is not the primary factor in the major types of deterioration and damage to which marble is susceptible. Problems and Deterioration The natural forces and agents of weather may have a degrading effect on the appearance and structural soundness of marble. These agents include rain, snow, temperature, wind and atmospheric pollutants. Weathering agents almost never work singly or in isolation, they always act in combination with one another or with other agents of deterioration. Rain water, especially in combination with atmospheric gases, can result in dissolution of the marble, creating higher levels of salt movement within the micro-structure. Temperature can effect rates of deterioration and (in larger stones) movement of the pieces, as well as patterns of salt migration within the stone. Higher temperatures often increase the rate of chemical changes; low temperatures can create the risk of "freeze-thaw" problems, and rapid changes of temperature can produce stresses in the material due to differential expansion. Most of the natural or inherent problems which can occur with marble require some degree of moisture to occur, however other problems such as wind erosion and vandalism may occur independently.

Natural or Inherent Marble Problems Weathering: Marble subjected to exterior exposures deteriorates due to weathering or the natural effects of wind, rain, and thermal change. Marble is extremely durable and because of its limited porosity does not absorb large amounts of water. It does, however, absorb some water and, since it is highly reactive when exposed to acids or even mildly acidic rain water, it can suffer substantial deterioration. In short, while the porosity of marble is low, the shape of the pores (elliptical) allows greater dissolution than in typical round pores, and this fact coupled with marble's inherent solubility in acids can result in two major problems: Loss of polish Loss of detailing The most common symptoms of weathering are a loss of the highly polished surface (where it exists) and loss of crisp edge details in decorative carved areas of the stone. Little can be done to restore edge detailing short of re-carving the stone which is usually infeasible. The gloss or polish can be maintained and, to some degree, restored on the surface of marble by using marble polishing powder and soft buffing pads.

Obviously the level of effort or labor required to repolish stone will depend upon the degree of deterioration of the surface, or loss of polish. New pieces, restored pieces or well-maintained surfaces can be retained in a highly polished state with much less effort than surfaces which have been exposed to weathering for long periods of time with little or no maintenance. For this reason, polished marble should receive regular preventive maintenance by polishing. Erosion: Erosion can be the result of general weathering described above, or it can be a more localized phenomenon based upon handling or exposure. Wind driven, airborne abrasives such as dirt, grit, and other "particles" may selectively wear away detailing. The effects will depend largely upon the direction of prevailing winds. One of the few effective ways to address this problem is by landscaping where plantings and/or landscape grade can deflect the wind. Such landscaping and/or grading may range from the simple and inexpensive to a major and expensive intervention. It would have to be consistent with the policy for the management of cultural landscapes. It may, however, be cost effective when considering the extended life of the building.

The symptoms of erosion can be as simple as the general loss of polish and edge sharpness as described above, or it can be very localized, specific wear due to contact with landscaping and mowing equipment. Localized damage due to contact by mowing or other maintenance equipment is preventable. Where there is evidence of recurrent physical damage, steps should be taken to protect the stone. Staining: Discoloration of the marble, whether general or localized, is staining. Staining may be the result of exposure to a variety of exterior substances, or to internal occlusions in the stone or structural elements. Some of the most common types of staining and the causative agents are: Oil/grease stains: These stains are usually the result of vandalism or handling. A variety of organic or inorganic oils may be absorbed into the stone upon contact. The depth of penetration will depend upon the viscosity of the oil/grease, temperature, stone porosity, finish and dryness. The appearance of grease/oil stains will usually consist of a darkening of the stone at the area of contact. The edges of the staining will generally be diffused, especially after an extended period. There are standard techniques for removing oil and grease stains and may often be accomplished by maintenance personnel..

For specific guidance on removing oil/grease stains from marble, see 04455-10-R and 04455-11-R. Dyes and inks: The staining can be any color depending on the type and source of the dye. This type of stain is likely to be extremely localized around the area of contact. The liquid containing the coloration may be absorbed into the stone and during the normal process of evaporation, the coloring pigment is deposited within the stone. For specific guidance on removing ink and dye stains from marble, see 04455-18-R. Organic stains: Organic stains are caused by direct contact with decomposing organic matter, such as leaves, bird or animal droppings, flowers, tea or coffee. Regardless of the source, these stains tend to be a slight reddish-brown in color. They also frequently disappear after the source has been removed. Organic stains may be left to weather and bleach or oxidize out after the removal of the organic source, however a residue may still remain on the stone. For specific guidance on removing organic stains from marble, see 04455-14-R.

Metallic stains: Two major categories of metallic staining are based on either iron or copper. The source of the staining may be internal structural components or features. A common source is the water wash, or run-off, from adjacent metallic elements, especially bronze. Rust stains: These stains are reddish-orange and are caused by the oxidation (rusting) of iron. The source of iron staining is usually the structural or connecting components. These components are usually hidden and protected; however, water penetration from bad joints or cracks can activate or accelerate rusting. The discoloration may be within the stone or it may be a deposit of rust on the surface of the stone. Surface deposits of rust may sometimes be removed by hand rubbing with a clean cloth. The examination of the stain should include such rubbing to determine if it is only a surface deposit. For specific guidance on removing rust stains from marble, see 04400-06-R. Copper stains: Stains from water run-off from bronze can range in color from a light green to a dark brown. The staining results from the dissolved copper salts (from copper or bronze) which wash down onto the stone, then oxidize.

The pattern of the staining is likely to be localized, streaked and in the path of the run-off from the metallic source. In some cases, especially plaques on stone, where biological growth or mildew may form on shaded elevations, the copper salts in the water running off the bronze acts as a fungicide, killing the growth and making areas directly below the metal look cleaner than surrounding areas. For specific guidance on removing copper stains from marble, see 04400-07-R. General dirt, soot and pollution: Marble can be discolored generally or locally by atmospheric dirt, grime and other airborne particulates which adhere to the material. The visual appearance is usually a dulling or graying effect which mutes or obscures the original color and gloss. Effects of dirt are usually intensified in the protected areas, where the rinsing effect of rain water is diminished. Dirt can be a complex composition of finely divided solids held together by organic material including soot, siliceous dust, and other airborne material. It may include particles of metals, glass, ceramics, metal oxides and minerals. Dirt is usually held to the surface by a combination of absorption and static attraction.

Dirt can become incorporated into "crusts" which can develop during the deterioration of some stones. Biological agents can also collect on dirty surfaces and the same water used for cleaning can stimulate algal growth. Algae, lichens and moss can produce acid by-products which can damage acid sensitive stone. In addition, some water proof and water repellent coatings used on stone actually increase the static attraction of the surface and result in the stone getting dirty faster. For specific guidance on removing dirt/pollution from marble, see 04400-01-P, 04400-02-P, 04400-03-P. Crumbling: This condition is due to a certain brittleness or tendency of the stone to break up or dissolve. It may be caused by an inherent weakness in the stone or gradual breakdown of the binder or crystalline structure, or it may be the result of external factors affecting the strength and durability of the marble. This condition may be caused by the use of de-icing salts, or any other source of salt migration, such as that which can occur when rising damp is present.

There is currently little which can be done to repair the damage once this condition has developed, however the early detection of potential problems and elimination of sources of salts is critical to arresting the process. When this condition is severe and obviously caused by the heavy or inappropriate use of de-icing salts, it is sometimes called "Salt Fretting". Regular preservation maintenance may eliminate the causes promoting crumbling, however, once the condition has occurred, its correction or repair is beyond the level of a maintenance procedure. The Regional Historic Preservation Officer (RHPO) should be contacted for assistance. Chipping: The separation of small pieces or larger fragments from a masonry unit, frequently at the corners, edges or mortar joints is known as chipping. These fractures are generally caused by deterioration and repointing, especially due to the use of too hard a pointing mortar, or by accident or vandalism. Repairs include detachment repairs, patching and splicing. Repair of chipped stone requires a skilled mason and is not a maintenance procedure. If chipping is due to occasional impact from mowing or other landscape maintenance, steps should be taken to prevent future damage For specific guidance on repairing chips in marble, see 04455-03-R.

Cracking: This condition is manifested by the appearance of narrow fissures ranging from less than 1/16 to 1/2 inch wide or more in the stone. It results from a variety of causes, such as structural overloading due to settlement, the use of too hard a mortar mix or a flaw in the material. Minor cracking may be no problem, in and of itself, but it can be an indication of structural problems and the cracks can be a source of entry of water into the interior of the stone, promoting salt migration. Marble is a relatively homogenous material since it is crystallized under intense heat and pressure. It has, however, evolved from sedimentary stones and may have structural/physical planes of different density and strength. Cracking, which allows water or salts to enter the stone, increases the possibility of failure along the planes with subsequent spalling. Repairs include patching and replacement. For specific guidance on repairing cracks in marble, see 04455-03-R. Detachment: This is not a failure of the marble, but rather a failure of the construction system, i.e. the connectors and/or joints.

The definition implies that the failed component survives intact and may be re-installed using appropriate mechanical techniques. Detachment cannot occur with a monolithic piece. Visually, detached pieces may be separated from surrounding ones. The failure of anchors or metal connectors which lead to detachment may be caused and/or accelerated by the penetration of water into the structure behind the stone, causing rust and corrosion. Adequate pointing and caulking will prevent leakage and penetration of water into the system. For specific guidance on re-securing detached marble, see 04455-21- R. Efflorescence: The appearance of a whitish deposit locally or uniformly over the surface may be efflorescence, the surface deposition of soluble salts. There are numerous sources for the soluble salts which create the hazy appearance; salts can come from mortar, improper cleaning agents, rising damp, de-icing salts, chemical landscaping treatments and air pollution. Whitish deposits of salts may be much less obvious on white marble than on darker stones and brick. On polished surfaces, deposits will reduce the gloss and present a diffuse or hazy area. Efflorescence can be a salt residue resulting from improper chemical cleaning, i.e.

too strong a chemical cleaner or inadequate rinsing. It can also be an indication of water problems. Salt migration and/or sub-florescence and efflorescence should be considered a symptom which should be investigated to identify the source of the soluble salts and/or the source of moisture. Corrective action should then be taken to eliminate the source of the problem once it is identified. Some efflorescence may occur naturally with new stones, mortar and installation materials. Normally, this efflorescence will be removed by natural rain and weathering processes and/or by regular washing. The new or continued appearance of efflorescence is a stronger indicator of problems like rising damp, inappropriate cleaning methods, all of which should be referred to the RHPO. For specific guidance on removing efflorescence from marble, see 04455-25-R. Erosion: Erosion is the wearing away of the material surface by the natural action of wind, windblown particles and water. It can occur with marble as well as any exposed materials. Inspections should include examination for any apparent loss of detail and edge sharpness which could be due to erosion.

Erosion may be less of a problem on rock-faced or quarry-faced marble, but may be a more serious problem on stone with more precise detail. Little can be done to correct this problem once it occurs, other than to protect the surface from further exposure to stop or retard the process. Flaking: This is an early stage of peeling, exfoliation, delamination or spalling evidenced by the detachment of small flat thin pieces of the outer layers of stone from a larger piece of stone. Flaking is usually caused by capillary moisture or freeze-thaw cycles which occur within the masonry. The problem can also occur due to sub-florescence, so that if flaking occurs, the area should be examined to determine if salt crystallization is occurring in the flaked areas. Peeling: Peeling is flaking away of the surface from the substrate in strips or layers. It may result from the improper application of masonry coatings which result in failure of the coating and/or stone surface. It may also result from a defect in the stone, or from weathering. Encrustation of the surface caused by chemical reactions with environmental elements may also peel or flake along the bedding plane.

Rising Damp: Rising damp is the suction of ground water into the base of masonry through capillary action. Moisture is drawn up into the marble and may rise and fall due to conditions of temperature; humidity; site grading; absence or failure of damp courses, and/or treatments to the masonry surfaces which affect evaporation. During active wet periods, rising damp may be visible as a darkening of the marble along the base at ground level. Due to the continuous changing of the moisture level due to varying exposure conditions, staining or efflorescence may be visible at a range of several feet up from the ground. Continuation of the problem can lead to more severe problems of flaking, peeling and/or spalling, but the correction of the problem requires the elimination of the source of water or the interruption of its path into the stone by physical or chemical damp-proofing. Spalling: Spalling is the separation and breaking away of pieces of stone due to sub-florescence, freeze-thaw, improper repointing with too hard a mortar mix or portland cement, or structural overloading of the stone. Spalling is less frequent with marble than with sedimentary stones which are also less dense.

Marble is dense enough to resist internal forces which would cause spalling in other natural stones or fabricated masonry. For specific guidance on repairing spalling marble, see 04400-03-R and 04455-03-R. Sub-Florescence: This is a potentially harmful internal accumulation of soluble salts deposited under or just beneath the masonry surface as moisture in the wall evaporates. The build-up of salts and their crystallization can create substantial pressures within the marble, causing pieces to break off along the planes of deposition. Efflorescence at the surface is an indication that sub-florescence is possible. Techniques for mitigating the problem include poulticing, removal of identified salt sources, elimination of moisture in the stone and damp-proofing. Sugaring: This is a gradual disintegration of the surface of the marble, possibly caused by salt migration and exposure to moisture. Excessive moisture may have the effect of dissolving the binder. Carbonate stones, especially fine grained marbles, are particularly susceptible to this form of deterioration. The surface takes on a rough granular, crystalline or sometimes powdery appearance. Last Reviewed 2016-08-02

Question: Marble is a form of which type of stone
Answer: Limestone