Chalcocite - definition of chalcocite by The Free Dictionary Chalcocite - definition of chalcocite by The Free Dictionary Related to chalcocite: arsenopyrite , covellite chal·co·cite A dark gray mineral, essentially Cu2S, that is an important ore of copper. [Alteration of obsolete chalcosine, from Greek khalkos, copper.] chalcocite (ˈkælkəˌsaɪt) n (Minerals) a lead-grey or black mineral, found as a copper ore or in veins. It is a source of copper. Composition: copper sulphide. Formula: Cu2S.

Crystal structure: orthorhombic [C19: changed from earlier chalcosine, from Greek khalkos copper + -ite1] chal•co•cite [1865–70; chalco - + (anthra) cite ] ThesaurusAntonymsRelated WordsSynonymsLegend: atomic number 29 , copper , Cu - a ductile malleable reddish-brown corrosion-resistant diamagnetic metallic element; occurs in various minerals but is the only metal that occurs abundantly in large masses; used as an electrical and thermal conductor mineral - solid homogeneous inorganic substances occurring in nature having a definite chemical composition Want to thank TFD for its existence? Tell a friend about us , add a link to this page, or visit the webmaster's page for free fun content . Link to this page: mineral References in periodicals archive ? A Red Metal geologist has visited site and confirmed the width of the vein and the nature of the mineralization and noted strong oxide, supergene mineralization consisting of chalcocite, azurite, malachite and tenorite.

Red Metal Resources Provides Mining Update for Farellon Property Among specific topics are microbial ecology in extreme acidic pit lakes of the Aberian Pyrite Belt in southwestern Spain, galactose as an inducer of the production of extracellular polymeric substances by Acidithiobacillus ferrooxidans, evidence for widespread dissimilatory hydrogen metabolism among acidophilic bacteria, immobilizing new isolated iron oxidizing bacteria on natural carriers, and the influence of pyrite on the galvanic assisted leaching of chalcocite concentrates. Ore minerals Short Courses IMPORTANT ORE MINERALS Most elements need to be concentrated into amounts that can be economically mined from ore deposits (usually hundreds to thousands of times their crustal abundance). This concentration is usually accomplished by dissolution of the element by hot water (hydrothermal ore deposits - gold, silver, lead), preferential crystallization from magmas (chromite deposits or pegmatites), surface weathering and leaching (aluminum, nickel, copper), or gravity separation of minerals during erosion (gold, diamonds, titanium). In the majority of cases there are only one or two minerals that provide all of a particular element for commercial uses.

Some elements in low concentrations (substituting in minor amounts for the major elements) are associated with minerals that are mined for other elements, but the shear volumes of materials that are processed result in a valuable byproduct (i e. elements associated with copper, lead, and zinc ores). Some elements are so valuable that almost any mineral containing that element in sufficient grades can be mined (gold, silver, platinum group). ELEMENTS Aluminum - The ore is mined from rocks that have been exposed to weathering in a tropical environment, bauxite. The main ore minerals in bauxite are gibbsite, bohmeite, and diaspore. Antimony - The primary ore of antimony is it's sulfide, stibnite. Arsenic - Recovered from other metal processing streams (primarily from the sulfosalts such as tennantite etc.). Arsenopyrite is the most common arsenic mineral. The relatively low demand for arsenic as compared to the amount of arsenic mined that is associated with other metals means it can be supplied from the waste streams of other ore processing. Barium - The chief source of barium is barite with minor production of witherite.

Beryllium - The major ore mineral for beryllium in the U.S. is bertrandite while worldwide the major source is from pegmatites that contain beryl. Bismuth - Primarily a byproduct of lead processing. Also found in a number of minerals such as bismuthinite and as a constituent in various sulfosalts. Boron - Chief source is playa lake deposits of borax, colemanite, kernite, ulexite. Bromine - Chief sources are brines from wells and Dead Sea. Cadmium - Unlike many other commodities cadmium is produced as a byproduct of zinc (sphalerite) mining. Cesium - The major ore mineral is pollucite, a pegmatite mineral. Production and use of this metal is extremely small (a few thousand kilograms per year). Chlorine - Produced from the mineral halite (rock salt). Chromium - The chief source is the mineral chromite which is found in large layered intrusives and serpentine bodies. Cobalt - The primary minerals for cobalt is cobaltite. Some cobalt is also produced from weathered tropical orebodies.

Columbium (see Niobium) Copper - Most copper ore bodies are mined from minerals created by weathering of the primary copper ore mineral chalcopyrite. Minerals in the enriched zone include chalcocite, bornite, djurleite. Minerals in the oxidized zones include malachite, azurite, chyrsocolla, cuprite, tenorite, native copper and brochantite. Gallium - A byproduct of zinc and alumina processing. Some primary "ore" may contain up to 200 ppm. Ga. Germanium - A byproduct of zinc ore processing. Also a deposit in China is associated with coal. Gold - The primary mineral of gold is the native metal and electrum (a gold-silver alloy). Some tellurides are also important ore minerals such as calaverite, sylvanite, and petzite. Hafnium - Primary ore mineral is zircon. Indium - Primarily is a byproduct of zinc processing. Iodine - Initial production was from seaweed. Iodine is extracted from natural gas field brines (up to 1200 ppm iodine in the brines).

Iron - Two major minerals in the production of iron are it's oxides, hematite and magnetite. These are found in preCambrian iron formations. Historically there was also production from goethite and siderite. The iron sulfides (pyrite and pyrrhotite) were not used as iron sources due to the difficulty of removing sulfur from the metals and the brittleness this sulfur caused in the metal. Lead - The primary ore mineral for lead is it's sulfide - galena. Some minor production from the past has come from secondary lead minerals - cerussite and anglesite. Lithium - The former primary ore minerals were pegmatite deposits of spodumene, lepidolite, and petalite, amblygonite. Currently the major U. S. production is from lithium carbonate brines. Magnesium - Although magnesium is found in many minerals, only dolomite, magnesite, brucite, carnallite, and olivine are of commercial importance. Magnesium and other magnesium compounds are also produced from seawater, well and lake brines and bitterns.

Manganese - The primary ores are oxides/hydroxides of manganese which include minerals such as hausmannite, pyrolusite, braunite, manganite, etc. and the carbonate, rhodochrosite. A large potential source is the deep sea manganese nodules. Mercury - The main ore is the sulfide, cinnabar. Molybdenum - The primary ore mineral is molybdenite. Nickel - The primary nickel ores are pentlandite, nickel bearing pyrrhotite and a weathering product, garnierite (a mixture of nÃ©pouite, pecoraite and willemseite). Niobium (Columbium) - The primary ore mineral is pyrochlore with minor columbite and tantalite-columbite. Phosphorus - Main ore minerals are in the apatite group of minerals (hydroxylapatite, fluorapatite, chlorapatite). Platinum group (Platinum, Osmium, Rhodium, Ruthenium, Palladium) - The primary ores are the native elements or alloys of the various elements or arsenides such as sperrylite.

They tend to occur in layered intrusives associated with chromite deposits. Potassium (potash) - The primary ore minerals are sylvite (primarily), brines, and langbeinite. Rare Earth elements (cerium, dysprosium, erbium, europium, gadolinium, holmium, lanthanium, lutetium, neodymium, praseodymium, samarium, scandium, terbium, thulium, ytterbium, yttrium) The major ore minerals containing rare earth elements are bastnasite, monazite, and loparite and the lateritic ion-adsorption clays. Major U.S. production of bastnesite is from Mountain Pass, California. Rhenium - Produced as a byproduct of molybdenite. Rubidium - Substitutes for potassium in lepidolite and pollucite. Production is small (a few thousand kilograms per year). Scandium (see Rare Earth) Sulfur | Minerals Education Coalition Necessary for all life. Description The origins of the name come from the Sanskrit language. Sulfur is a non-metallic bright yellow solid.

It has been known since antiquity, being the brimstone found in the Bible. Sulfur occurs in many different forms or allotropes, and they are always mixed with each other, which makes the chemistry of sulfur quite complicated. Sulfur can appear in many different colors, such as orange, brown or red. Sulfur is stable in air and water and is often found in its pure elemental form. Sulfur is a very important industrial element, used in many different processes. Its primary use is in the production of sulfuric acid, which is the most heavily used chemical in the world, and mostly is used to make superphosphate fertilizers. The U.S. alone produces 200 pounds of sulfuric acid for every man, woman and child in the country every year. Sulfur is also important in the production of vulcanized rubber, gunpowder, in petroleum refining, and in the synthesis of many sulfur-bearing organic molecules. Pure sulfur is an excellent electric insulator, but not often is used as such. Biological Benefits Sulfur is an essential element to all life. It is a primary constituent of two important amino acids, methionine and cysteine.

It is also a minor constituent of fats, body fluids and bones. Role in Life Processes Essential for life processes in plants animals. Percentage Amount in the Human Body: 0.2% Sources Sulfur is mined from pure sulfur deposits found in oil-producing regions in Louisiana, Texas, Canada and Mexico. It is also found in pure form near volcanoes and hot springs. Other sources of sulfur are the mineral pyrite and hydrogen sulfide gas distilled from natural gas wells especially in the Middle East and Canada. Sulfur is a common constituent of crude oil, from which it also is obtained. There are many sulfur-bearing minerals. Among the most common are anhydrite (calcium sulfate), barite (barium sulfate), chalcocite (copper sulfide), chalcopyrite, cinnabar (mercury sulfide), galena (lead sulfide), kieserite (magnesium sulfate), gypsum, sphalerite (zinc sulfide), and stibnite (antimony sulfide). Minerals, elements and the Earthï¿½s crust Minerals, elements and the Earthï¿½s crust Introduction Minerals are substances formed naturally in the Earth. They have a definite chemical composition and structure.

There are over 3000 minerals known. Some are rare and precious such as gold and diamond, while others are more ordinary, such as quartz. Do you know of any more examples of minerals from the Earth? Like all substances, minerals are composed of elements . There are only about a hundred elements, and they are the basic building blocks of everything around us. They can be found either in their pure form or chemically combined with other elements to make compounds . A compound is two or more elements chemically joined together. What you will need A copy of the Periodic Table. The activity Elements in the Earthï¿½s crust Almost 99% of the minerals making up the Earthï¿½s crust are made up of just eight elements. Most of these elements are found combined with other elements as compounds. Minerals are elements or compounds that occur naturally in the Earthï¿½s crust. Rocks are mixtures formed of minerals. Just as elements are the building blocks of minerals, so minerals form the building blocks of rocks. Table 1 gives some information about the most common elements in the Earthï¿½s crust in order of abundance.

Element name Percentage by weight of the Earthï¿½s crust Oxygen 1 Table 1 The elements in the Earthï¿½s crust The ï¿½otherï¿½ elements include copper, uranium, gold and silver. Although they are comparatively rare, these are very important to mankind. Q 1 . Table 1 shows the relative amounts of the elements making up the Earthï¿½s crust. Draw a bar chart to show this information. Q 2 . Which is the commonest element in the Earthï¿½s crust? Q 3 . Which is the rarest single element in the Earthï¿½s crust of those named in Table 1? Q 4 . The most common elements in the Earthï¿½s crust are rarely found on their own. They are usually found combined. Suggest why this is. Q 5 . What do we call two or more elements chemically combined together? Q 6 . Suggest which element in Table 1 might be the most expensive. Give a reason why you cannot be certain about your prediction. Mineral names and chemical composition Table 2 gives the names of some minerals and their chemical formulae.

The chemical formula of a mineral tells us what elements it contains and in what proportions. Mineral name Table 2 Mineral names and chemical composition Q 7 . The mineral galena contains the elements lead and sulfur combined in a 1:1 ratio. Half the atoms in the mineral are lead. Pyrite has iron and sulfur combined in a 1:2 ratio; only one third of the atoms are iron. Fill in the columns headed ï¿½How many atoms of each element are present in the formulaï¿½ and ï¿½Useful elementï¿½ in Table 2 (above). Use your Periodic Table to help you. Q 8 . Which of the minerals chalcopyrite and chalcocite contains the highest proportion of copper atoms? (Hint. Add up the number of different atoms in each mineral and work out how many of them are copper atoms). Q 9 . Suggest which copper mineral would be most profitable to mine for copper? Give a reason why you cannot be certain about your prediction. Q 10 .

Use your research skills to find out about the uses of the elements in the ï¿½Useful elementï¿½ column of Table 2 and put them in the ï¿½Usesï¿½ column of this table. Q 11 . For each of the ï¿½useful elementsï¿½ in Table 2, find out: their properties Copper - Mineral Fact Sheets - Australian Mines Atlas Suggestions for Further Reading Introduction Copper (Cu) has a cultural significance as it was the first metal used by man (probably as early as 7000 BC). Neolithic man mined native copper and used it as a substitute for stone; its malleability enabled easy shaping of tools by beating it. Copper was smelted as early as 3500 BC at Timna in Israel. Its property of alloying with other metals (particularly tin) was discovered about 500 years later and heralded the Bronze Age, which started in southern Europe between 3000 and 2500 BC. Although the manufacture of bronze tools largely fell into disuse with the onset of the Iron Age about 1000 BC, copper continued to be used for its other properties.

As one of only two coloured metals, its beauty makes it highly desirable for making ornaments and its resistance to corrosion makes it suitable for use in, or near the sea. The growth of the copper industry has been intimately linked with the increasing use of electricity with electrical applications continuing to be the metal's principal use which can be attributed to two physical properties. It is an excellent electrical (and heat) conductor and is ductile enough to be drawn into wire and beaten into sheets without fracturing. Copper is used widely in plumbing components and is a major component of alloys, many of which are harder, stronger and tougher than their individual constituent elements. Occurrence The main ore mineral of copper in Australia (and worldwide) is chalcopyrite (CuFeS2). Bornite (Cu5FeS4), covellite (CuS) and chalcocite (Cu2S) are important sources in the world, and many ore bodies also contain some malachite (CuCO3.Cu(OH)2), azurite (Cu3(CO3)2.Cu(OH)2), cuprite (Cu2O), tenorite (CuO) and native copper.

The sulphides, which yield most of the copper produced throughout the world, generally occupy the deeper parts of lodes which have not been exposed to weathering. Near the surface they are altered by oxidation and other chemical actions to the native metal, oxides and carbonates. These secondary copper minerals may form rich ore in the upper parts of many deposits, and, owing to their characteristic green or blue colour, even small amounts are easily seen in the rocks in which they occur. Australian Resources and Deposits Copper is widely distributed in Australia in rocks of Precambrian and Palaeozoic age (more than 250 million years old). Australia's resources of copper are largely at the Olympic Dam copper-uranium-gold deposit in South Australia and the Mount Isa copper-lead-zinc deposit in Queensland. Other important copper resources are at the Northparkes copper-gold, CSA copper-lead-zinc and Girilambone copper deposits in New South Wales, the Ernest Henry, Osborne and Mammoth copper deposits and copper-gold deposits at Selwyn in Queensland and copper-zinc deposits at Golden Grove and the Nifty copper deposit in Western Australia.

Australia's main copper mining centres are in the Mount Isa/Cloncurry region of Queensland and at Olympic Dam in South Australia. The Mount Isa mine, which also produces large tonnages of lead, zinc and silver, currently is the largest copper producer in Australia and is one of the world's biggest underground mines. At Mount Isa, the copper ore bodies are separate from the lead-zinc-silver ore bodies, thus enabling independent production of the two ore types. Across Australia, relatively small amounts of copper are recovered as a by-product of silver-lead-zinc, nickel and gold mining. Several important copper deposits have been discovered in the past 30 years. By far the largest of these is the copper-uranium-gold deposit discovered in 1975 at Olympic Dam where expanded annual production will soon surpass that at Mt Isa.

Other important discoveries include the Northparkes copper-gold deposit (NSW) in 1977, Cadia copper-gold deposit (NSW) in 1993, Benambra copper-zinc deposit (Vic) in 1978, Scuddles (Golden Grove) copper-lead-zinc deposit (WA) in 1979, Selwyn gold-copper deposit (Qld) in 1980, Nifty copper deposit (WA) in 1983, Eloise copper-gold deposit (Qld) in 1988, Osborne copper-gold deposit (Qld) in 1990, Ernest Henry copper-gold deposit (Qld) in 1991, Tritton copper deposit (NSW) in 1995, and Ridgeway copper-gold deposit (NSW) in 1996. Australia in the World Australia has about 6% of the world's economic copper resources and is ranked third after Chile (25%) and the USA (16%). In production Australia is ranked fifth after Chile, USA, Indonesia and Canada.

Mining and Processing Although large copper deposits are mined by open-cut methods in many of the major producing countries, most of the copper ore produced in Australia comes from underground mines. At some Australian mines, the copper is leached from the ore to produce a copper-rich solution which is later treated to recover the copper metal. At the Mount Gordon mine (formerly Mammoth) at Gunpowder in Queensland the ore is first broken and set out on leach pads where it is dissolved by a sulphuric acid solution to leach out the copper. The copper-rich solution is then pumped to the solvent extraction plant to separate the copper as a copper complex. This is concentrated and the solution is passed to the electrowinning plant to recover the copper. The copper cathodes produced by electrowinning contain 99.99% copper which is suitable for electrical uses. This entire process, known as solvent extraction electrowinning (SX-EW), is used at other mines treating copper oxide ores, most notably at Girilambone and at Nifty. The traditional method used at most mines involves the ore being broken and brought to the surface for crushing.

The ore is then ground finely before the copper-bearing sulphide minerals are concentrated by a flotation process which separates the grains of ore mineral from the waste material, or gangue. Depending on the type of copper bearing minerals in the ore and the treatment processes used, the concentrate can contain between 25 and 57% copper. The concentrate is then processed in a smelter. Smelters are operated at Mount Isa and Olympic Dam. Copper refineries are operated at Townsville, Olympic Dam and Port Pirie (a small refinery subsidiary to the large lead-zinc refinery). Various methods of smelting are used to convert the concentrates to copper metal. One method is to melt them with fluxes in a smelter furnace to produce copper matte, which is a mixture mainly of iron and copper sulphides usually containing 50 to 70% copper. The molten matte is poured into a converter, which contains more fluxes, and converted into blister copper, which is about 98 to 99% pure. The blister copper is tapped, further refined in an anode furnace and finally electrolytically refined to pure cathode copper. At Olympic Dam the concentrate is flash-smelted directly to blister copper.

In this process copper concentrate is fed into the smelter with oxygen-enriched air. The fine concentrate reacts or 'flashes' instantaneously as the sulphur fraction of the copper sulphides is burnt and becomes sulphur dioxide gas. Molten copper and slag fall to the hearth of the smelter. The slag forms a layer on the surface of the molten blister copper. The blister copper is removed periodically for further purifying in an anode furnace and electrolytically refined. Copper is alloyed with other metals to give it special properties. Bronze is an alloy of tin and copper. The earliest bronzes were natural alloys derived from mineral deposits which also contained tin. Brass is an alloy of zinc and copper and is used extensively in marine applications because of its resistance to corrosion. Uses Copper is an excellent conductor of electricity. More than half of the copper consumed is used in electrical generators and motors, electrical power and lighting fixtures, electrical wiring, radio and television sets, computers and almost everything electrical. Copper also conducts heat well and is used for thin-walled copper tubing in air conditioning and refrigeration units, motor vehicle radiators, home heating systems, steam condensers etc.

Copper's corrosion resistance and ease with which it can be joined make it suitable for plumbing fittings and water reticulation systems, automotive fuel lines, sea water desalination plants and hydraulic systems. The blue-green colour of treated timber is the result of copper naphthanate and copper-chrome-arsenate which have been introduced under pressure to help protect the wood from borers. Copper sulphate is used as a fungicide and as a trace element in fertilisers. Copper is used also for making coins and scientific instruments as well as in decorative applications. Suggestions for Further Reading Bester, G. (Ed) 1999 Register Of Australian Mining 1999/00, Resource Information Unit Ltd, Perth. Blainey, G. 1960 Mines In The Spinifex - The Story Of Mount Isa Mines, Angus & Robertson, Sydney. Blainey, G. 1978 The Rush That Never Ended: A History Of Australian Mining, 3rd edition, Melbourne University Press, Melbourne.

Photos of Natural Silver Ore, Silver minerals, Crystal ores, rich Silver quartz specimens Silver Ores and Silver Bearing Minerals Gold and silver are obtained from a variety of ores, in some of which the gold predominates, in others silver is the primary value, while in still a third class these two metals may be mixed with the base metals, such as lead, copper, zinc, and iron. Few silver ores are absolutely free from gold, and vice versa, so that a separate consideration of the two is more or less a difficult task. For ores where the most valuable element is silver, the silver is normally contained in minerals colored gray to black in appearance. These minerals range from a metallic sheen to an earthy soot-like appearance. Sooty black minerals are common in many very rich silver ore samples. Most of these sooty black deposits consist of acanthite or various complex silver sulfides.

The most common valuable minerals which may constitute rich silver ores include native silver; acanthite (silver sulfide); pyargyrite (dark ruby silver or silver antimony sulfide); Proustite (light ruby silver or silver arsenic sulfide); Stephanite (brittle silver, also a silver antimony sulfide); Polybasite (also a silver antimony sulfide); Cerargyrite (Silver Chloride); Bromyrite (silver bromide) and Iodyrite (silver Iodide). Bonanza grade silver ore can also contain various silver telluride minerals including Calaverite , Sylvanite and Hessite. To a lesser extent, base metal sulfides including Galena , sphalerite , pyrite , chalcopyrite , and chalcocite may all be and frequently are argentiferous, but in most silver ore deposits, the silver is most concentrated in the minerals of the group first named. Of the base metal ore minerals, the most common primary ones are argentiferous galena, sphalerite, and pyrite, while native silver and the sulphides and arsenides are less common. Rich silver ore from the town of Tonopah in Nye county Nevada.

Tonopah was one of the great epithermal silver and gold strikes of the early 20th century. The bonanza ore is rich in silver sulfides and also contains some free gold as well. Dark colored minerals of an almost sooty appearance are rich in silver. Rich lead - silver ore from the famous mines of Wallace, Idaho. These mines have been mined to very deep levels below the surface. Dark colored high grade ruby silver ore (pyrargyrite) from the rich Nevada Mines at Battle Mountain in Lander County. Although Silver was the first metal discovered here, Battle Mountain has also produced a significant amount of both gold and copper ore as well as silver. This sulfide rich silver ore from Nevada is dark gray and colored by a heavy content of metallic sulfides. The rich silver minerals pyrargyrite and stephanite boost the silver content of this bonanza grade ore. The Silver Peak mining district in Esmerelda County, Nevada was very productive in the late 1800s, but work continued through the early 1900s, and is still a site for ongoing open pit gold mining to this day. This area produced many millions of dollars from silver ore which looked like this specimen.

It is colored gray by rich silver and lead sulfide minerals. This bonanza grade silver ore is from Nye County in Nevada. As with a number of the samples, the sooty black minerals are rich in silver. It also contains silver tellurides. Telluride minerals such as calaverite, are also important silver ores in some mining districts. This sample of rich gold and silver ore comes from the Cripple Creek district in Colorado. The mossy metallic colored mineral on this specimen is calaverite, a mineral rich in both gold and silver. The Comstock lode district was perhaps the largest single silver ore find ever made in the USA. The Comstock lode is famous for its ore bodies of bonanza grade silver ore rich in sooty silver sulfide minerals like acanthite (formerly known as argentite). The ore also contains considerable other sulfide minerals and some free gold as well. The Comstock is famous for great bonanzas of crushed, mineralized quartz, in part exceedingly rich in silver minerals, were found at intervals along the lode, especially in chambers or vertical fissures probably produced by normal faulting of the hanging wall.

The ores consist of quartz and some calcite, in places banded with pyrite, galena, chalcopyrite, sphalerite, and finely distributed rich silver minerals. The valuable minerals are mainly native gold, acanthite (argentite), stephanite, and polybasite. For Gold Prospecting: Rhodochrosite and silver ore, Peru: This beautiful specimen of silver ore comes from the country of Peru in South America. The dark colored minerals are the ones which are silver bearing, while the red and pink colored crystals are Rhodochrosite, a common manganese mineral that is found in a number of silver ores. Standard Types of Silver Ores: There are two general classes of silver ore that have been mined: 1) lead-silver and 2) high-grade silver ores. Both have almost always varying amounts of gold. The lead -silver mines furnish also, as noted above, by far the greater portion of the lead produced in the United States. High grade silver ores normally have considerably less base metal content and often contain significant gold. 1. Dry or Siliceous Ores.

These include: (a) The gold and silver ores proper, including bonanza epithermal silver ores; (b) fluxing ores carrying considerable quantities of iron and manganese oxides with small gold and silver contents; (c) precious-metal bearing ores with copper, lead and zinc in small amounts; and (d) disseminated low grade silver deposits. The states of Colorado, California, Nevada, South Dakota, and Alaska have been the largest producers of this category of silver ore The siliceous ores are in part free milling; in part simply concentrating, as parts of Colorado and Arizona; in increasing part all-sliming and cyaniding; and in part smelting. A great deal of the silver from the gold-silver siliceous ores is obtained with the gold by cyanidation, the silver being recovered by refining the mill bullion. The remainder is obtained by smelting rich ores and refining copper or lead bullion produced. The siliceous silver ores are of varying age, but most epithermal ores are young, typically post-Miocene age. Those found chiefly in Colorado, Nevada, and Montana, are associated with Tertiary lavas and characterized by Bonanza grade rich ores.

Some of the most productive ones may carry fluorite and normally also tellurides. In some the value of the gold may predominate; in others, silver. 2. Copper ores, usually with over 1 per cent copper, but with less in the case of the western disseminated ores and those of Lake Superior. The largest gold producers are those of Utah, Arizona, Nevada, and Montana. The silver production comes from the electrolytic refining of blister copper produced by smelting. The great disseminated deposits of Utah, Arizona, Nevada, and New Mexico are yielding increasing quantities, while the vein deposits of places like Butte, Mont., have are also been important. The gold- and silver-bearing copper ores exhibit great differences in form and age; neither do all the occurrences yield much gold or silver, and, moreover, they are of more importance as gold producers, silver being less often associated with the copper. 3. Lead-bearing Silver ores: These are silver ores containing 4 percent or more of lead. The silver comes mainly from the lead-silver ores of Coeur d'Alene, Idaho, Utah (chiefly Park City and Tintic), Colorado (Leadville and Aspen).

Most of the output is obtained by the de-silverization of lead bullion using molten zinc. The silver and lead ores form a large class, of rather wide distribution, and while the two metals characterizing the group are the most prominent, there may also be, and often is, present a variable quantity of other metals such as gold, zinc, and copper. The silver contents, though sometimes high, but are not necessarily visible, and may be contained within the galena as Ag2S partly replacing lead sulfide in the crystal. The ore bodies as a whole present a variety of forms, the ore having been deposited either by fissure vein cavity filling or replacement, or both. Most of the important occurrences seem to have been formed at intermediate depths. Oxidation zones frequently cap the ore bodies, and downward secondary enrichment has probably occurred in many cases. Silver-lead ores form a widely distributed class in the Cordilleran region of the United States and supply most of the lead mined in this country. Prominent deposits have been mined in Colorado, Idaho, and Utah, but are also known in New Mexico, Montana, Wyoming, Nevada, Arizona, California, and South Dakota.

Canada supplies a small but steady production from British Columbia, while in other foreign countries districts worth noting for either commercial or historic importance are Broken Hill, New South Wales, Australia; Clausthal and Freiberg, Germany; Przibram, Bohemia; Sala, Sweden; Laurium, Greece; Mexico, etc. 4. Copper-lead or Copper-lead-zinc Ores. These are unimportant as compared with the others. The gold they supply is small, and the main silver production was from mines in Colorado and Nevada. Historically, the Eureka district in Nevada yielded significant amounts of copper-lead-zinc ore with large amounts of gold and silver. They are often designated as polymetallic ores in modern classification systems. 5. Zinc ores, containing at least 25 per cent zinc. These yield little gold, and the silver which is obtained mainly as a by-product from the smelting of zinc ore concentrates and in the US has been obtained chiefly from deposits in Nevada, Montana, and Arizona.

If you haven't seen my original crystal nugget page, beautiful nugget photos: CRYSTAL GOLD NUGGETS A second page of beautiful nugget photos: GOLD AND PLATINUM NUGGETS I also have a page of beautiful Gold Ore Specimen photos: GOLD ORES AND MINERALS For more information on gold vein ores, check out my page of CALIFORNIA MOTHER LODE GOLD QUARTZ VEINS To learn about the minerals that produce copper, check my page of COPPER ORES AND MINERALS Please note these specimens are not for sale, most are not owned by me. I present this page as a reference, as folks just love to look at real natural beauty and these silver ore specimens are definitely that. Photographs and text are copyrighted and may not be reproduced without permission. Nevada Outback Gems Geological ore deposits - Australian Museum Australian Museum Geological ore deposits are of many different types and occur in all geological environments. The main types of geological ore deposits of importance can be divided into: metallic deposits fossil fuel deposits Finding ore deposits Geologists are always searching for more ore deposits to meet constant demand.

This has become more difficult with time as easily accessible ore deposits close to the Earth's surface have already been exploited by humans in the past. Therefore, more complex techniques have been developed to locate new deposits. However, better and more efficient processing techniques now mean that we can exploit ore deposits which were previously uneconomic. Economic viability of ore deposits Many factors control the economic viability of an ore deposit but the most important are: grade (i.e. amount of metal per ton of rock) size of the deposit (i.e. tonnage) easy access to infrastructure such as roads and rail for transportation current price for the commodity demand Oxidised zones of ore deposits The region above the water-table in an ore deposit is known as the oxidised zone as it is the zone of oxidation of the primary ore minerals. This oxidised zone is primarily composed of mixtures of iron oxides/hydroxides and quartz which we call gossan. Most primary ore minerals (particularly the sulfide minerals) are only stable in anaerobic dry environments. With the rise and fall of the water-table and downward percolating rainwater (containing dissolved oxygen), these minerals dissolve and new minerals (oxide zone minerals) are precipitated in the gossan.

With the dissolution of sulfide minerals, the water becomes acidic, further enhancing the dissolution of the ore. Most of the spectacular minerals we see from ore deposits are those formed in the oxidised zone. When the oxidised zone is well developed and the secondary minerals sufficiently concentrated, it is a highly profitable zone to mine as the processing is much cheaper and easier and the metals more concentrated. However, most oxidised zones have been mined in the past because they formed outcrops of easily identifiable stained gossans. The most common minerals found in oxidised zones are: Copper: malachite, azurite, chrysocolla Classification and types of mineral deposits Geologists classify mineral deposits in many different ways, according to the: commodity being mined tectonic setting in which the deposit occurs geological setting of the mineral deposit genetic model for the origin of the ore deposit The most commonly used scheme is the genetic classification scheme. These deposits include: Orthomagmatic deposits are those that form from primary magmatic processes (i.e. magmas). They are hosted in the igneous rocks in which they have formed. Most of the world's nickel, chromium and platinum-group elements are derived from these deposits.

The largest deposits of platinum-group elements and chromium come from the 2055 million year old Bushveld Complex of northern South Africa. Orthomagmatic deposits include: chromium molybdenum tungsten Hydrothermal deposits cover a wide range of different deposits types but all form from hot circulating water-rich fluids. These include the two main types of gold deposits - epithermal and lode gold deposits along with replacement deposits in calcareous sequences (Mississippi Valley deposits), base-metal vein deposits and replacement skarn deposits Volcanic or extrusive deposits are associated with volcanic processes and are only found within the volcanic rocks themselves. Important deposits of gold, mercury, antimony, copper and base metals are of this type. The largest deposits of this type are known as kuroko or volcanogenic massive sulfide deposits (commonly abbreviated as VMS deposits). These have formed on the ocean floor by circulating hydrothermal fluids emanating from a volcanic vent which leach metals from the surrounding volcanic rocks. They are currently forming on the sea floor and these are commonly referred to as black smokers.

Remobilisation of ore deposits As many ore deposits formed many hundreds to thousands of millions of years ago, many have experienced numerous episodes of deformation and metamorphism which left them with few characteristics of their original form. Many of the ore components were remobilised (i.e. moved) either by physical (i.e. deformation) or chemical (i.e. dissolution and precipitation) mechanisms. The Broken Hill lode in far western New South Wales is an excellent example of this. It has undergone numerous episodes of deformation and metamorphism with the ore bodies themselves being strongly folded, faulted and metamorphosed. Archaean gold deposits Archaean gold deposits account for more than 60% of the world's gold. Over 60% of this comes from the Witwatersrand of South Africa (a hydrothermally remobilised palaeo-placer gold deposit) and the remainder from Archaean lode gold deposits in Australia, Canada, southern Africa and South America.

The Archaean granite-greenstone belts of the world are characterised by numerous lode gold deposits, the largest of which is the Superior Province of Canada which has produced more than 170 million ounces of gold (a troy ounce is 31.1 grams). In Australia, most Archaean lode gold deposits occur in the Norseman-Wiluna greenstone belt of Western Australia (this includes the famous Kalgoorlie Golden Mile containing the Super Pit, an open-cut gold operation that has dimensions of 3 km x 1 km x 1 km). These gold deposits are generally of large tonnage (millions of tonnes), and low-grade (commonly 1.5 - 3 g/T), confined to very narrow, mostly steeply-plunging near-vertical structures and are sulfide-deficient. They are confined to the volcanic-intrusive-sedimentary sequences of the greenstone belts and not the granites. There is a very strong structural control to Archaean lode gold deposits with most being related to regional fault systems. The gold mineralisation usually occurs at the contact between the veins and wallrocks.

Most of the ore in these deposits is of the disseminated type with the gold mineralisation generally being invisible to the naked eye. The formation of these deposits is linked to regional-scale processes at mid-crustal levels during regional metamorphism. Epithermal gold deposits These deposits are related to convergent-margin tectonic settings such as that of the Andes, South America. They are volcanic-hosted deposits (consisting of both subvolcanics and sub-aerial pyroclastics) that are generally relatively recent in age (e.g. Mesozoic to the present-day). In general, they are small (less than a million tons) but rich (up to 500g/T) deposits which consist of vein systems and bonanza ores (e.g. the El Indio deposit of Chile contains 120 000 tons at 250g/T and 3.2 million tons at 12.3g/T). Epithermal gold deposits occur over a considerable length (tens of kilometres) but are of limited vertical extent (on average, 350 m). They are ancient volcanic structures, most commonly collapsed craters and calderas.

Epithermal gold deposits essentially form by the boiling and mixing of primary hydrothermal fluids at temperatures of 230° C - 260° C. The hydrothermal fluids themselves are derived from deeper subvolcanic or plutonic rocks. Initially, fracturing of the host rock occurs under high fluid pressures and these fractures then act as channel-ways for the hydrothermal fluids. The ore itself most commonly occurs in veins, breccia zones, stockworks and replacement zones. The ore minerals are generally fine-grained, and quartz pseudomorphs after calcite are characteristic of these deposits. Hydrothermal alteration of the volcanic host rocks is a characteristic of these deposits, and the gold is usually associated with zones of silicification. The main ore minerals are: native gold and silver silica occurring as quartz (most often forming comb-like aggregates), amethyst, opal, chalcedony and cristobalite Sedimentary iron ore and manganese deposits Most of the world's iron and manganese are derived from deposits of this type. These deposits are very large in size (thousands of millions of tons) and are usually mined by open-cut methods.

The iron and manganese ores occur as distinct sedimentary layers alternating with iron and manganese-poor sedimentary layers - the whole mass is sometimes mined. Iron ores of this type are commonly termed the banded iron formation or simply abbreviated as BIF All ore minerals in these deposits are oxides and hydroxides. The most common iron ore minerals are hematite, lepidocrocite and goethite while the most common manganese ore minerals are braunite, manganite and hausmannite. These deposits are believed to have formed in shallow marine basins and are confined to Proterozoic rock sequences. They are believed to have formed as chemical precipitates on the floor of the shallow oceanic basins in a highly oxidising environment. As they are very ancient, most of these deposits have been intensely deformed and metamorphosed. Bog Iron ore was formerly mined in Europe hundreds of years ago when the large iron ore deposits had not been discovered. It consists of iron hydroxide (goethite) deposited in swamps and lakes as a product of bacterial action.

Placer deposits These are made of alluvial, colluvial and eluvial material, which contain economic quantities of some valuable minerals: Alluvial: Detrital material which is transported by a river and usually deposited along the river's pathway, either in the riverbed itself or on its floodplain. Colluvial: Weathered material transported by gravity action such as on scree slopes. Eluvial: Weathered material still at or near its point of formation. The most common placer deposits are those of gold, platinum, group minerals, gemstones, tin, rutile, monazite and zircon. For a mineral to be concentrated in a placer deposit, it must be resistant to weathering and erosion and have a relatively high specific gravity. The placer deposits usually form from primary deposits in which the ore mineral is widely disseminated and uneconomic. Concentration occurs when the surrounding rock is eroded away and the heavy ore mineral becomes concentrated by erosional processes. During transport of this material, concentration can occur within depressions, such as where a river changes its speed or in river bends. Recently formed marine placer deposits of rutile, monazite and zircon are currently being exploited along the coast of eastern Australia.

These are very important as they are our main source for the elements titanium and zirconium. Fossil placer deposits are also of great importance, with the world's largest gold deposit, the Witwatersrand reefs of South Africa, an excellent example. Clay deposits These either form by settling of clay particles in sedimentary basins or through intense weathering of volcanic and granitic rocks. They generally occur as lens-shaped bodies and are most commonly mined by open-cut methods. The most common clay minerals mined are kaolinite, illite and montmorillonite. Useful clay types include: China Clay: deposits of kaolin produced by hydrothermal decomposition or deep weathering of feldspar minerals in granites. Fullers Earth: an aluminium-poor montmorillonite clay which is highly absorbent (very useful for absorbing contaminant oil). Evaporite deposits An evaporite is a sediment that forms through the evaporation of saline water. The most common evaporite deposits are salts (most commonly sylvite and halite), gypsum, and nitrates. Most evaporites are derived from bodies of sea-water, but under special conditions, inland lakes may also give rise to evaporite deposits, particularly in regions of low rainfall and high temperature.

The original character of most evaporite deposits has been destroyed by replacement through circulating fluids. An ideal evaporite sequence (in decreasing order of solubility) is as follows: Potassium and magnesium salts (kainite, carnallite, sylvite) type 1 Rock salt (halite) - type 2 Gypsum (below 42° C) or anhydrite (above 42° C) - type 3 Calcite and dolomite - type 4 As evaporite beds of types 1 and 2 consist of highly soluble minerals, they are commonly re-dissolved by the influx of new salt-water. To be preserved, they must be covered over quickly by an impervious layer. Since sea-water only contains 31 parts per thousand of dissolved salts, even evaporation of large areas of sea-water will only result in the deposition of a thin evaporite layer. For thick, economically viable evaporite layers to be deposited, a continuous evaporation-replenishment system must operate. Salt domes: under conditions of high pressure, salt deforms plastically and behaves like a magma deforming and piercing through the overlying sediments.

They are of economic importance as they form oil traps and can sometimes contain economic deposits of sulfur and boron. Phosphatic deposits Phosphorite is a commonly used term for lithified phosphate rock. The island of Nauru in the Pacific is one of the world's largest deposits of phosphorite and has been mined since at least the 1950s. The mineralogy of phosphate deposits is very complex. They usually consist of fine-grained mixtures of various calcium phosphates with the most common mineral being apatite. Collophane is an amorphous calcium phosphate that is also commonly found in phosphate deposits. Phosphate deposits are of three main types: Primary marine phosphate deposits: All marine sediments, particularly limestones, contain some phosphate, which under particular conditions may rise to a greater concentration than normal (phosphatic limestone), but rarely reaching an economically extractable concentration. These deposits are rare and usually arise from either the leaching of the phosphatic limestone (dissolving away the calcium carbonate and leaving behind the detrital phosphate) or the extraction of phosphate at higher levels followed by secondary concentration from downward-percolating groundwaters. These deposits occur under relatively cool conditions in an oxygen-free environment.

Bone beds: These are localised accumulations of fossil deposits of bone, teeth, scales and excreta (i.e. coprolites) that are occasionally thick enough to form economic deposits. These have mostly been mined in the past. A good example of bone beds is the marsupial-rich bone phosphate deposits of the Wellington Caves near Dubbo, New South Wales. Guano: These are ancient and/or fossil deposits of bird or bat excreta. Guano deposits from birds are most commonly found on oceanic islands. Guano deposits from bats are found in large cave systems. Guano deposits need a dry climate for their preservation. Organic deposits Coal Coal is a general name given to stratified accumulations of carbonaceous material derived from vegetation. The starting material is usually peat or some other form of partially decayed organic material (commonly leaves and branches of trees). Combined processes of compaction (from overlying sediments) and slight heating converts this organic material to black coal.

There are several stages in this process that occur with increasing heat and compaction: Peat Lignite (also known as brown coal) Sub-bituminous coal Sub-anthracite Anthracite This sequence shows a progressive increase in carbon content with corresponding decrease in volatile content. The percentage of carbon in a dry mineral-free coal is called the rank. Individual components of coal are known as macerals, of which there are three main types, vitrinite, exinite and inertinite. Fireclay Fireclay is a fossil clay-rich soil associated with coal deposits. It is useful as a refractory material. Peat Peat is a partially decomposed mass of vegetation that has grown in a shallow lake or marsh. Peat contains recognisable vegetable material but very little mineral material. The main plants which make-up peat are the peat mosses, along with rushes, sedges and horse-tails. Peat deposits may be tens of metres thick and cover a large area. Peat deposits form in areas of high rainfall, usually under temperate to cold climatic conditions. Peat deposits have long been used (particularly in Northern Europe) as a source of fuel.

Oil/petroleum Natural deposits of oil are most commonly found associated with natural gas (which is itself derived from the heating-up of the oil), salt water, and sometimes, solid hydrocarbons. The origin of natural oil is still disputed but most geologists believe that it is derived from organic material by decay. Most natural accumulations of oil appear to have formed under marine conditions (i.e. marine basins) though some has also formed in estuarine and deltaic environments. Natural accumulations of oil are rarely found where they initially formed because the oil is a fluid and migrates easily through any openings in rocks such as pores in sedimentary rocks, joint planes, cleavage planes, bedding planes and fractures. During migration, the oil-water system breaks-up with the oil floating on the water. Unless this migration of the oil is prevented it will flow to the surface with the liquid parts evaporating, leaving behind the solid hydrocarbons such as waxes and asphalts. For oil to be exploitable, it must be trapped by an impermeable geological barrier.

There are two main types of such traps, structural traps (such as folds or faults) and stratigraphic/lithological traps (such as salt domes, overlying impermeable sedimentary layers). The oil-bearing strata itself has to be pervious or porous so that the oil can flow freely through it. Oil usually contains many different hydrocarbons that have differing boiling temperatures. Those that have the lowest boiling temperature become accumulations of natural gas which, being lighter than the oil, forms a gas-cap on top of the oil accumulation. The pressure of this gas cap on the overlying strata and the upward pressure of any underlying water below the oil layer are used to drive the oil towards the surface without the need for pumping. Kerogen: a solid organic material that yields petroleum-type hydrocarbons on heating and distillation. Tar pits: small areas where soft asphaltic tar wells up to the surface and fills a hollow. Oil shale: this is a fine-grained black or dark grey clay-rich sedimentary rock that yields liquid hydrocarbons upon distillation (i.e. heating). Most oil shale deposits are associated with coal.

Though oil shales were exploited in the early parts of the twentieth century, they are now uneconomic because of the low price of petroleum and the high cost of processing. Residual deposits Residual deposits are formed in tropical regions. During the wet season, intense leaching of the rock occurs. Then, during the dry season, the solution containing the leached ions is drawn towards the surface by capillary action where it evaporates leaving behind salts that are washed away in the next wet season. Eventually, the whole zone down to the base of the water table is leached of relatively mobile ions such as sodium, potassium, calcium and magnesium. With leaching under the right pH conditions, silica is also dissolved and removed from the system. The remaining material is usually just iron and aluminium oxides which are concentrated. Many fossil laterites are known and these provide evidence of former tropical environments. Basic and ultrabasic rocks tend to form laterites while granitic rocks lead to the development of bauxite. In some tropical regions, where the laterite is developed on ultrabasic rocks, it forms important deposits of nickel, usually at the base of the laterite zone.

In New Caledonia, these deposits are extensively mined and the main nickel-bearing phases are amorphous nickel silicates. Other areas which contain extensive laterite nickel mineralisation are the Norseman-Wiluna greenstone belt of Western Australia and Central Africa. Some of these laterites also contain elevated levels of the platinum-group elements which are an important by-product of the mining. The problem with these deposits is that the nickel is often very difficult to extract from the laterite. Ian Graham It's Elemental - The Element Copper It's Elemental Melting Point: 1357.77 K (1084.62°C or 1984.32°F) Boiling Point: 2835 K (2562°C or 4644°F) Density: 8.933 grams per cubic centimeter Phase at Room Temperature: Solid Element Classification: Metal Period Number: 4 Group Number: 11 Group Name: none What's in a name? From the Latin word cuprum, which means "from the island of Cyprus." Say what? Copper is pronounced as KOP-er.

History and Uses: Archaeological evidence suggests that people have been using copper for at least 11,000 years. Relatively easy to mine and refine, people discovered methods for extracting copper from its ores at least 7,000 years ago. The Roman Empire obtained most of its copper from the island of Cyprus, which is where copper's name originated. Today, copper is primarily obtained from the ores cuprite (CuO2), tenorite (CuO), malachite (CuO3·Cu(OH)2), chalcocite (Cu2S), covellite (CuS) and bornite (Cu6FeS4). Large deposits of copper ore are located in the United States, Chile, Zambia, Zaire, Peru and Canada. Used in large amounts by the electrical industry in the form of wire, copper is second only to silver in electrical conductance. Since it resists corrosion from the air, moisture and seawater, copper has been widely used in coins. Although once made nearly entirely from copper, American pennies are now made from zinc that has been coated with copper. Copper is also used to make water pipes and jewelry, as well as other items.

Pure copper is usually too soft for most uses. People first learned about 5,000 years ago that copper can be strengthened if it is mixed with other metals. The two most familiar alloys of copper are bronze and brass. Bronze, the first alloy created by people, is a mix of copper that contains as much as 25% tin . Early people used bronze to make tools, weaponry, containers and ornamental items. Brass, a mix of copper that contains between 5% and 45% zinc, was first used about 2,500 years ago. The Romans were the first to make extensive use of brass, using it to make such things as coins, kettles and ornamental objects. Today, brass is also used in some musical instruments, screws and other hardware that must resist corrosion. Hydrated copper sulfate (CuSO4·H2O), also known as blue vitriol, is the best known copper compound. It is used as an agricultural poison, as an algicide in water purification and as a blue pigment for inks. Cuperic chloride (CuCl2), another copper compound, is used to fix dyes to fabrics.

Cuprous chloride (CuCl) is a poisonous white powder that is chiefly used to absorb carbon dioxide (CO2). Copper cyanide (CuCN) is commonly used in electroplating. Estimated Crustal Abundance: 6.0×101 milligrams per kilogram Estimated Oceanic Abundance: 2.5×10-4 milligrams per liter Number of Stable Isotopes: 2 ( View all isotope data ) Ionization Energy: 7.726 eV

Question: Chalcocite is an important ore of which metallic element?
Answer: COPPER