U.S. Department of the Interior

U.S. Geological Survey

Circular 1314

From Projectile Points to Microprocessors—

The Influence of Some Industrial Minerals
From Projectile Points to 

Microprocessors—The Influence of Some 

Industrial Minerals

By Rhonda Driscoll

Circular 1314

U.S. Department of the Interior

U.S. Geological Survey
U.S. Department of the Interior

DIRK KEMPTHORNE, Secretary

U.S. Geological Survey

Mark D. Myers, Director

U.S. Geological Survey, Reston, Virginia: 2007

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Suggested citation:

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U.S. Geological Survey Circular 1314, 26 p.

FRONT COVER

Stone remains of the Barlow and Sanderson Mail and Stage Line station, a spur off the Santa Fe Trail, circa 1870.

Comanche National Grasslands, Vogel Canyon, La Junta, Colo. Photograph by author.
iii

Contents

Abstract...........................................................................................................................................................1

Introduction.....................................................................................................................................................1

The Versatile Nine .........................................................................................................................................1

Bentonite-Montmorillonite..................................................................................................................1

Halite (Salt).............................................................................................................................................4

Portland Cement....................................................................................................................................6

Zeolite .....................................................................................................................................................9

Borates .................................................................................................................................................13

Gypsum.................................................................................................................................................15

Industrial Sand ....................................................................................................................................17

Talc ........................................................................................................................................................17

Stone Products—Aggregate, Dimension Stone, and Abrasives................................................19

Final Words ...................................................................................................................................................23

Selected References...................................................................................................................................23

Appendix. Domestic and World Production of Industrial Minerals....................................................25

Figures

1. Photographs of Lower Paleolithic handaxes...........................................................................2

2. Photograph of ancient Great Zimbabwe walls built of shaped 

stone bricks ...................................................................................................................................3

3. Aerial photograph of an Oakland, Calif., freeway system .....................................................3

4. Photograph of unusual gemmy blue bentonite crystals on natrolite...................................3

5. Sketch conceptual model of montmorillonite soil crack development 

owing to repeated drying ............................................................................................................5

6. Photograph of pink halite (salt) crystal hand specimen ........................................................5

7. Diagram showing salt solution mining......................................................................................7

8. Aerial view of salt evaporation ponds in West Texas.............................................................7

9. Drawing showing how, as concrete sets, particle nodes grow to connect with 

other nodes ...................................................................................................................................8

10. Photograph showing concrete masonry and cast products for 

the garden......................................................................................................................................8

11. Aerial view of large concrete dam, Glen Canyon Dam, Colorado River............................10

12. Sketch reconstruction of city of Babylon and photograph of excavated ruins ...............10

13. Photograph of a portion of the Great Wall near Yumenguan Pass, People’s 

Republic of China........................................................................................................................11

14. Photographs of Roman ruins at the seaport of Ostia ...........................................................11

15. Schematic diagrams of zeolite structure................................................................................12

16. Diagrams showing zeolite ion exchange................................................................................12

17–20. Photographs showing:

17. An example of the legendary “20-mule team” hauling borax....................................13

18. Colemanite crystals...........................................................................................................14
iv

19. Flowering Indian paintbrush as an example of plant cycles aided by boron 

content in soil .....................................................................................................................14

20. Gypsum mine in badland topography near Salina, Utah.............................................15

21. Sketch illustrating extent of wallboard use—from Earth to Moon, and 

circumscribing the Earth ...........................................................................................................16

22. Photograph of synthetic silicon crystal in hand specimen .................................................18

23. Photograph of sand as a golfer’s menace on a golf course bunker ..................................18

24. Scanning electron microscope images of microcrystalline talc........................................20

25–27. Photographs showing:

25. Relative sizes of pebbles, sand, and gravel ..................................................................20

26. Uses and production of aggregate.................................................................................21

27. Uses of aggregate abrasives...........................................................................................22
Abstract

In the language of economic geology, Earth materials 

are classified as metallic ores, fuel minerals, gemstones, and 

industrial minerals. Most people know that metallic ores yield 

shiny, conductive, ductile elements such as copper, iron, or 

gold. And nearly everyone understands that energy-producing 

coals constitute a fuel mineral. Likewise, dazzling rubies and 

rare sapphires are universally recognized as gemstones. The 

fourth group, industrial minerals, is largely unknown to the 

general public, even though industrial minerals are as essential 

to daily life as metals and fuel minerals. This report examines 

in brief the occurrence and practical uses of nine industrial 

minerals, selected for general interest as well as their importance. The minerals profiled in this report represent only a 

few of the more than 50 industrial minerals that shape human 

culture.

Introduction

Since the time of early humans, natural Earth materials have contributed to the species’ survival and progress. 

Principal among these natural materials have been stone, salt, 

and, with the advance of time, clay, gypsum, and dozens more 

nonmetallic, nonfuel substances known today as industrial 

minerals.

In the beginning primitive hunters clobbered prey with 

rocks. Later, men stalked food with carefully crafted stone 

weapons, such as spear points and dart tips (fig. 1).

Later still, humans discovered a method of food preservation using salt. They built food storage structures and family 

dwellings using adobe clay and stones (fig. 2). And when the 

hunters became farmers, they devised irrigation systems by 

lining shallow diversion canals with native rock.

As towns and city centers appeared, so too did levees, 

paved streets, administrative buildings, and tiled baths—the 

construction of which derived from regional limestone, sandstone, granite, clay, and other available rock material.

Fast forward a few thousand years and marvel at seemingly limitless industrial minerals applications. From paints 

to fuel additives, feedlots to fish farms, freeways to nuclear 

reactors, industrial minerals are at the center of modern affluent existence (fig. 3).

As you read you will recognize a truth: most of what you 

do or have or rely on can be connected to industrial minerals. 

The Versatile Nine

Industrial minerals can be found in everyday consumer 

goods such as house paint and pet products. They are also 

present in uncommon, special purpose products like conductive plastics (graphite) and solar cell electric power generators 

(tellurium). This report examines only 9 of the approximately 

50 most utilized industrial minerals. These nine minerals are 

among the most abundant in their natural state and are most 

likely to be found in products and processes worldwide.

Bentonite-Montmorillonite

Discovered in 1890 near Fort Benton, Wyo., bentonite is 

a rock that contains colloidal silica and assorted clay minerals 

including montmorillonite. Montmorillonite, whose chemical 

formula is (Na)0.7(Al3.3 Mg0.7) Si8O20(OH)4

.

nH2O, belongs to 

a group of clay minerals referred to as smectites—minerals 

which tend to swell when wet and shrink when dry (fig. 4).

Swelling occurs when water penetrates and enlarges 

the interlayered molecular spaces of the smectite structure. 

Shrinking occurs when detached water molecules leave 

voids in the smectite lattice, causing the structure to collapse.

It is this alternate swelling-shrinking property that makes 

bentonite-montmorillonite both a constructive and a destructive natural material.

As a constructive agent, bentonite has many industrial applications. It is used by oil, gas, and water extraction 

industries as a drilling mud. In a semi-fluid state bentonite is 

extruded through the drill bit to keep the bit cool and lubricated as it bores through rocks into a petroleum deposit or an 

aquifer. Trailing the drill shaft is a thin stream of montmorillonite-fill. This wet fill expands into cracks and fractures along 

the wall of the borehole, adding stability and strength. Later, 

when a well so constructed is exhausted, industry once again 

relies on bentonite. Clay-rich bentonite chips are loaded into 

From Projectile Points to Microprocessors—

The Influence of Some Industrial Minerals 

By Rhonda Driscoll
2 Projectile Points and Microprocessors—Influence of Industrial Minerals

Figure 1. Lower Paleolithic handaxes. A, Large Acheulian handaxe (Lower Paleolithic, 2,000,000 to 200,000 B.C.E.), 

13 cm long, culture unknown. B, Large Acheulian handaxe, 17 cm long, from Maghreb (the region of northwest Africa 

including Morocco, Algeria, and Tunisia). C, Acheulian handaxe, 11 cm long, from Kasai, Democratic Republic of the 

Congo, Central Africa. Photographs Wladyslaw Kowalski, Pennsylvania State University.

A B

C
Figure 3. Aerial view of an Oakland, Calif., 

freeway system; date unknown. Photograph 

Michael Collier, from the American Geological 

Institute image library. Image source Earth 

Science World Image Bank http://www.

earthscienceworld.org/images.

Figure 4. Uncommonly gemmy blue bentonite crystals on 

natrolite. Bentonite usually occurs as a fine-grained gray to graywhite mass. Photograph by Stonetrust, Inc., from the American 

Geological Institute image library. Image source Earth Science 

World Image Bank http://www.earthscienceworld.org/images.

Figure 2. Ancient Great Zimbabwe walls built of shaped stone 

brick, near Masvingo, Zimbabwe. The walls were constructed 

around 1200 B.C.E. Photograph A.J. Mandolesi, from the 

American Geological Institute image library. Image source Earth 

Science World Image Bank http://www.earthscienceworld.org/

images.

The Versatile Nine 3
4 Projectile Points and Microprocessors—Influence of Industrial Minerals

the decommissioned borehole where, upon wetting, they swell 

to form a permanent solid clay seal and contamination barrier 

within and outside the borehole.

The metals industry has also discovered uses for bentonite. In a process called green sand casting, sand of uniform 

composition and size is blended with coal dust, cellulose, 

silica flour, bentonite, and water. In a moist state the sand 

mixture is squeezed, or molded, into hollow shapes into which 

molten metals are poured. Bentonite in the sand mixture serves 

two functions: in a moist or hydrated state, bentonite swells to 

hold the sand mold together, and in a dry or dehydrated state, 

bentonite acts as a thermal expansion buffer by absorbing 

excess heat that would otherwise distort the mold.

The paper industry and the pet products industry have 

also found practical applications for bentonite. The former 

uses sodium bentonite to capture effluent and flocculent in 

paper-making processes, while the latter adds montmorillonite 

clay to commercial cat and bird litters. Because of its moisture 

absorbent property, bentonite-montmorillonite can wick up 

unwanted, impure, and malodorous fluids.

Bentonite-montmorillonite has even found its way onto 

feedlots and croplands. It is used as a binder in livestock food 

pellets and as a carrier for herbicides and pesticides applied 

to cultivated soils. In addition, bentonite soil applications can 

improve soil properties such as aeration, permeability, holding 

capacity, and nutrient uptake. Improvements such as these 

can be especially valuable in areas where rainfall amounts are 

minimal. During dry cycles the bentonite dehydrates, releasing 

moisture and nutrient solutions to root soil horizons.

The benefits of bentonite-montmorillonite are indisputable, but it is the destructive quality of the mineral that 

causes the most concern for land developers and homeowners. 

Because bentonite-montmorillonite expands and contracts 

(hydrates and dehydrates) in changing moisture conditions, it 

can ruin building foundations and sidewalks. It can also damage costly landscaping and subsurface sewage and communication systems. As rainwater soaks into underlying bentonite 

soils, absorption and expansion occur. Expanding clay can 

swell to several times its dry volume, pushing against concrete 

foundations, conduits, and cable lines with enormous force. 

Over time, this expansion pressure can produce cracks or 

distortions in concrete support walls; it can sever PVC pipe, 

fiber-optic cables, and critical plant roots.

Conversely, dry weather can dehydrate, or shrink, bentonite soils. Shrinkage produces voids in the soil into which 

sod, basements, driveways, or steel cables collapse by inches, 

or even feet! Figure 5 illustrates part of the story. Structural 

repair costs associated with active bentonite-montmorillonite 

soils are in the billions of dollars annually. 

Despite its destructive potential, bentonite-montmorillonite contributes to modern industries and modern comforts in 

ways generally unknown and unacknowledged. 

Halite (Salt)

Halite, or sodium chloride (NaCl), is a critical industrial mineral. It occurs naturally as cubic crystals (fig. 6) in 

underground domes or bedded sedimentary layers, and on the 

Earth’s surface as the residue of ancient seas.

Halite is much more than the white granular food seasoning used worldwide. Historically, it was a soldier’s pay, a 

warlord’s leverage, a nomad’s rank, and a tribesman’s talisman. Today’s uses are just as practical. Nowhere is this practicality more evident than in the chemicals industry, the largest 

consumer of salt. A short list of the more familiar chemicals 

produced from a sodium chloride base includes:

•	 Chlorine (Cl)—a bleaching product, a germicide, a 

compound element

•	 Caustic soda (NaOH, sodium hydroxide)—a neutralizing agent in the petroleum, pulp, paper, and alumina 

(aluminum oxide, Al2O3, an ingredient of ceramics and 

insulation) industries 

•	 Sodium chlorate (NaClO3)—a pesticide, herbicide, and 

oxidizer (a substance that supports the combustion of 

fuel) 

•	 Sodium sulfate (Na2SO4)—used in the manufacture of 

soaps and detergents 

•	 Hydrochloric acid (HCl)—a rust- and scale-removal 

agent, a component of batteries and fireworks. 

To obtain these and other derivative compounds, the two components of halite—sodium (Na+

) and chlorine (Cl-)—must be 

separated and concentrated. This is accomplished by dissolving salt in an oxidized solution (separation). Once the salt is 

dissolved, the solution is passed through a magnetic filtration 

system that captures the chlorine atoms (concentration). The 

sodium or chlorine concentrate can then be mixed with other 

elements to create new chemical compounds.

The use of salt is by no means confined to the production 

of chemicals. Salt is used as a dietary supplement for livestock 

and poultry. Agricultural studies confirm that salt contributes 

to the good health and optimum growth of feedlot and freeranging food animals.

Livestock aren’t the only beneficiaries of salt. Urban 

commuters travel with more confidence on wintertime roads 

treated with rock salt. Salt is still the most commonly used 

roadway de-icer. As it converts solid ice to liquid water, its 

own solid state is unaffected. It facilitates the melting process 

by increasing the kinetic energy of H2O molecules. That it can 

do so to a maximum low temperature of 15°F (–9°C) makes 

salt one of the more fascinating industrial minerals (About..., 

2004).

Salt can affect water in another important way. It can 

be used as a water softener or conditioner. “Hard” water 

contains excess dissolved calcium (Ca) and (or) magnesium 

(Mg). When salt is added to hard water, it behaves like a trap, 
Figure 5. Conceptual model of montmorillonite soil crack 

development owing to repeated drying. (Modified from 

Dexter, 1998.)

The Versatile Nine 5

Figure 6. Pink halite (salt) crystal measuring 3x4x4 in.; specimen locality unknown. 

Photograph by author.

A tensile stress

B primary cracks

C + secondary cracks

D + tertiary cracks

tensile stress

primary cracks

+ secondary cracks

+ tertiary cracks
6 Projectile Points and Microprocessors—Influence of Industrial Minerals

snaring calcium and magnesium ions. By capturing “hard” 

calcium and magnesium atoms, salt becomes an economical 

water-softening agent. “Soft” water requires less detergent and 

soap for laundering, cleaning, and bathing.

In dry and drought-stricken areas, sodium chloride is distributed in the warm troposphere to produce rain. When ideal 

stratus clouds form at low altitude, aircraft release salt into 

targeted portions of the cloud mass. Moisture droplets in the 

cloud layer collect on the salt grains (a hygroscopic attraction) 

until the combined weight of the droplets and salt forces their 

fall to the Earth’s surface (NAWC, 2003).

Every day, Earth’s approximately six billion people 

depend on salt. In the past 100 years, annual global salt 

production has increased from 10 million tons to 200 million 

tons (U.S. Geological Survey, 2004). North America produces 

about one-quarter of the world’s salt.

Salt is produced by four methods:

•	 Solution mining: Water is injected into an underground 

salt bed or salt dome, which dissolves the salt and produces a brine (fig. 7). The brine is pumped to an aboveground evaporation site. From there, concentrated “dry 

salt” is transported to chemical plants.

•	 Solar evaporation of sea water or saline lake water: 

Natural sun and wind evaporation takes place in brine 

ponds until salt crystals appear (fig. 8). Crystallization begins at a sodium chloride concentration of 25.8 

percent.

•	 Vacuum pan evaporation: A concentrated brine solution is chemically treated to remove impurities such as 

magnesium (Mg), calcium (Ca), and sulfate (SO4

2–). 

The concentrate is ultra-dried using a centrifuge, 

vacuum, or kiln. The resulting food grade salt is then 

fortified with iodine (I) to prevent iodine deficiency 

disorders such as goiter, dwarfism, and certain types of 

mental retardation.

•	 Deep shaft (rock salt mining): In a typical underground 

rock salt mine, heavy machinery cuts a narrow corridor 

through a section of a deposit. Holes are drilled into 

the walls of the corridor and packed with dynamite; 

when the charge is detonated, the corridor walls collapse. Miners operating electric shovels then move 

in to scoop the salt onto train cars or dump trucks, 

gradually carving caverns, or rooms, supported by salt 

pillars. The extracted salt is hauled to below- or aboveground crushers. Once crushed, the salt is passed 

through giant sieves. A system of conveyors moves the 

salt to size-specific piles. Commercial carriers arrive 

to load and transport the salt to outlying plants for 

additional treatment or storage. 

To locate underground salt deposits, energy waves created by seismometers are sent underground. The waves are 

reflected back to surface recorders called geophones. The 

recorders capture data signals that are translated into “maps” 

or profiles of subsurface features. This method of finding and 

profiling salt deposits is called reflection seismography. Seismographs reveal either salt domes called diapirs, or salt beds 

buried by sedimentary layers. Salt beds range from tens of feet 

to several thousands of feet thick. Domes are often more than 

1 mile in diameter and 15,000 feet in vertical length. 

To describe a friend as “salt of the Earth” is high praise 

indeed. It suggests value, versatility, and complexity.

Portland Cement

Portland cement itself is not an industrial mineral. It is 

a manufactured product consisting of limestone, shale, and 

(or) other naturally occurring materials. All Portland cements 

are discrete compounds—stand-alone masonry material. 

But, when blended with aggregate, Portland cement becomes 

concrete. A typical mixture of concrete contains 11 percent 

Portland cement, 41 percent coarse aggregate, 20 percent sand, 

6 percent air, and 16 percent water (W.H. Langer, written commun., 2005). When water is added to the mix, a node (black 

semi-triangle, left side of fig. 9) begins to form on the surface 

of each cement or aggregate particle (irregular outline, fig. 9). 

The node grows, or expands, to link up with nodes of other 

particles until the concrete exhibits a standard stiffness (Portland Cement Association, 2004). The concrete is then poured, 

compacted, floated, trowelled, and cured. What many people 

don’t know is that curing doesn’t end when concrete is dry 

and appears impenetrable. Curing is a process that continues 

for the life of the concrete—as it ages concrete gets stronger, 

albeit at a very slow rate.

Types of concrete include:

•	 Ready-mixed—3⁄4 of all concrete shuttled in the familiar revolving drum trucks (van Oss, 2004) 

•	 Pre-cast—concrete bricks, bridge girders, and structural components 

•	 Concrete masonry—cast in many shapes, configurations, colors, and textures to satisfy architectural 

design (fig. 10) 

•	 Cement-based materials such as mortar, grout, and 

terrazzo 

•	 Advanced products that incorporate fibers and special 

aggregates to create roofing tiles, sidings, and countertops.

A classification reference developed by the American 

Society for Testing and Materials (ASTM International, 2004) 

lists types of Portland cements and their recommended uses:

•	 Type I Portland cement is a general-purpose construction cement used in buildings, bridges, floors, and 

pavements.
Figure 7. Solution mining. Pressurized water is pumped into underground salt 

deposits through a borehole; the dissolved salt, called brine, is pumped to a 

topside processing plant. Diagram courtesy www.saltsense.co.uk.

Figure 8. Aerial view of salt evaporation ponds in West 

Texas. Photograph Michael Collier, from the American 

Geological Institute image library. Image source Earth 

Science World Image Bank http://www.earthscienceworld.

org/images.

The Versatile Nine 7

30 m

200 m
8 Projectile Points and Microprocessors—Influence of Industrial Minerals

Figure 10. Red concrete masonry birdbath and flower 

pot, and cast concrete garden elf without added color. 

Photograph by author.

Figure 9. Particle nodes grow to connect with other nodes within setting concrete, forming a dense mass. 

Ink illustration by John Driscoll.
•	 Type II has been developed for resistance to minor 

sulfate (SO4

2–, a salt of sulfuric acid (H2

SO4)) present 

in some building projects or processing environments.

•	 Type III is used when the combination of rapid set and 

strength gain is required.

•	 Type IV develops strength at a slow rate and generates 

low heat. It is used in massive concrete structures such 

as dams (fig. 11).

•	 Type V is used for masonry structures that are exposed 

to very high levels of sulfate derived from soils or 

ground water.

Though all Portland cement hardens under water, not all 

are suitable for underwater structures. A specialty mixture 

that includes Portland cement, granulated blast furnace slag, 

fly ash, pozzolana (siliceous volcanic ash), and silica fume (a 

byproduct of silicon metal production) can be poured directly 

into submerged forms.

Expansive Portland is yet another special application 

cement. As its name implies, this cement expands slightly as it 

hardens. Used almost exclusively in bridge deck construction, 

expansive cement reduces the occurrence of drying-shrinkage 

cracks. It also contributes to the overall tensile, or tension, 

strength of the elevated deck. 

Before the discovery of Portland cement in 1824, 

cements, or mortars, of varying composition were used to 

build structures. A gypsum mortar was used in the construction of some Egyptian pyramids. The ancient Babylonians 

used lime-based mortars to build fortifications and irrigation 

canals; the Chinese constructed parts of the Great Wall with a 

mud-and-straw mortar (figs. 12, 13).

But it was the Romans (c. 300 C.E.) whose mortar formulas were the most innovative. Lime, sand, pozzolana, animal 

fat, milk, and blood were all used as admixtures. The Roman 

Empire succeeded, in large part, because of Roman cement 

technology (fig. 14). Evidence of their expertise is found in a 

letter from a provincial governor to the emperor: Around 112 

C.E. [Common Era; formerly A.D.], Roman Emperor Trajan 

(98–117 C.E.) appointed Pliny the Younger as governor of 

Bythinia (present-day northern Turkey). Upon his arrival in 

the Bythinian capital of Nicomedia, Pliny discovered a city 

in a state of disrepair and a guild class practiced in larceny. 

Many public buildings were dilapidated; public works projects 

were incomplete and over budget. In correspondence with 

Trajan, Pliny described, among other construction fiascos, a 

gymnasium project: “***the architect asserts that the walls, 

although twenty-two feet thick, cannot bear the weight placed 

upon them, because they have not been put together with 

cement***” (Davis, 1912). 

Like all educated Roman citizens of the time, Pliny 

appreciated the strength of cement. Today, advances in 

chemistry as well as in computer simulation continue to foster 

appreciation for this durable admixture.

The importance of Portland cement cannot be exaggerated. It is used everywhere. Science and industry have invested 

untold billions and conducted countless experiments in an 

ongoing effort to create inexpensive, long-lasting, conditionspecific cements and concretes—terra firma synthesized!

Zeolite

Zeolites, like clay minerals, are alumino-silicates. Unlike 

clays, which have a two-dimensional layered structure, zeolites have a three-dimensional structure similar to a honeycomb (fig. 15). This framework of interconnected tunnels and 

cells allows for free movement of gases and solutions through 

the mineral interior. And, because the stacked tunnels have 

nearly uniform dimensions, zeolites can act as molecular 

sieves, screening molecules of varying size and shape. 

It is this “screening” property that makes zeolites a most 

important and wonderful industrial mineral.

To understand the phenomenon of molecular sieving, a 

few terms and concepts have to be explained. The first of these 

is ions—positively or negatively charged atoms or molecules. 

Cations, such as Na+, are positively charged ions. Anions are 

negatively charged. An example of an anion is Cl–. Next is 

ion exchange—a chemical reaction in which equal numbers 

of ions of identical charge and similar shape and size are 

exchanged between two substances. Zeolite minerals have 

a superior ion exchange capacity. As ionized fluids or gases 

diffuse in and out of the zeolite structure, ion exchange occurs. 

Thus, for example, potassium (K+) and sodium (Na+)ions from 

a zeolite framework can be exchanged for ammonium ions 

(NH4

+

) present in a soil. The ammonium cations fit neatly into 

the zeolite structure, while the liberated potassium and sodium 

cations are dispersed throughout the soil as a plant micronutrient. The charge balance and structural integrity of the zeolite 

are preserved, and potentially toxic ammonium is removed 

from the soil and replaced by an essential plant nutrient (fig. 

16).

This exchange process is called “sieving.” The capacity of zeolite minerals to selectively exchange ions in almost 

any environment, without damage to its own porous structure, 

makes it an ideal mineral for many industrial and commercial 

applications. One such application can be found in the commercial meats industry. Beef, pork, and poultry producers rely 

on zeolite to control ammonia (NH3) and hydrogen sulfide 

(H2S), two unpleasant gases associated with the decomposition of organic waste. By dusting approximately 1 lb of zeolite 

over a square foot of animal waste pile, offensive gases can be 

minimized or eliminated by cation exchange. The zeolite can 

then be transferred from the waste enclosure to cultivated acreage where it slowly releases the nitrogen (N) component of the 

ammonium (NH4

+

) to the nutrient uptake system of plants.

Zeolite has also been adapted to aquaculture. In fish 

rearing environments, NH4

+ toxicity (from fish excrement) can 

be reduced by adding a zeolite substrate to the water filtering 

system. The zeolite substrate provides a second benefit—that 

of a constructive bacteria nursery. Some bacteria populations 

convert NH4

+ (a weak base also known as ammonia water or 

The Versatile Nine 9
10 Projectile Points and Microprocessors—Influence of Industrial Minerals

Figure 11. Aerial view of Glen Canyon Dam on the Colorado River. Photograph by Michael 

Collier, from the American Geological Institute image library. Image source Earth Science 

World Image Bank http://www.earthscienceworld.org/images.

Figure 12. Construction in the ancient city of Babylon. A, artist reconstruction of the city; B, excavated ruins of the city. Photographs 

Fairfield University, www.fairfield.edu.

A B
Figure 14. Roman ruins at the seaport of Ostia. Apartments located near the baths (top); firefighters’ barracks 

near the harbor (bottom). Ostia had 100,000 inhabitants at its peak. The emperor Trajan spent considerable 

money enlarging and improving Ostia. Photograph David Chaszar, www.ancient-rome.tripod.com.

Figure 13. A view of a nearly forgotten portion of the Great Wall 

near Yumenguan Pass, People’s Republic of China; a relic of the Han 

Dynasty built of reeds, tamarisk twigs, sand, and mud. Photograph 

www.travelchinaguide.com.

The Versatile Nine 11
12 Projectile Points and Microprocessors—Influence of Industrial Minerals

Figure 16. Zeolite ion exchange process. Fresh zeolite is pictured on the left. Sodium 

and potassium are ready to be exchanged with other ions. Right diagram illustrates 

release of Na+ and K+ in exchange for ammonium ions. Illustrations Jens Kallmeyer, 

GeoForschungsZentrum, Potsdam, Germany.

K+

Na+

K+

Na+

K+

Na+

Na+

K+

K+

Na+

K+

K+

Na+

Na+

NH1

+

NH1

+

NH1

+

NH1

+ NH1

+

Na+

K+

NH1

+

NH1

+

Figure 15. Schematic diagrams of the zeolite structure. 

Illustration www.iza-structure.org. “Catalog of Disorder in Zeolite 

Frameworks,” H. Gies and H. van Koningsveld. Published on 

behalf of the Structure Commission of the International Zeolite 

Association. Copyright © 2000 International Zeolite Association.

4

4

4

4

4

4

4
ammonium) to NO3

, thereby aerating, or oxygenating, the 

water system.

This excellent mineral has found its way into power generating plants. Power plants burn carbon-based (organic) fuels 

and emit air-polluting gases called VOCs (volatile organic 

compounds). To reduce these kinds of emissions, the stacks of 

some coal-fired power plants are lined with zeolite concentrators. Sulfur-containing waste gases are absorbed by the zeolite, 

thereby reducing the volume of sulfur oxides vented into the 

atmosphere. And, because zeolite is unaffected by the extreme 

heat of emission VOCs, it does not deteriorate over time (U.S. 

EPA, 1998).

Zeolite use in the automobile engine is even more ingenious. When gas engines are cold, they emit VOCs in their 

exhaust. Zeolite, in the engine’s catalytic converter, adsorbs1

the cold engine emissions. As the engine warms up, the hot 

exhaust gases are desorbed from the zeolite and converted to 

an oxidized fuel. Thus, in a conventional combustion engine, 

zeolite prevents volatile gases from escape to the atmosphere 

and facilitates reuse of those very same VOCs. Amazing!

Another amazing zeolite application is its adaptation 

to the treatment of radioactive waste. Two radioactive elements, cesium (Cs) and strontium (Sr), accumulate in reactive 

wastewater. By introducing powdered zeolite to the wastewater, as much as 1 μg (microgram (one millionth of a gram)) 

radioactive Cs and Sr per liter of water can be exchanged in 

the zeolite structure—a significant exchange rate (D.R. Liles, 

oral commun., 2005). When ion exchange reaches capacity, 

the zeolite is collected and mixed with concrete. The concrete 

is then cast as drums which can be disposed of in a landfill or 

in the oceans. Saltwater, either on land or in the sea, seems to 

have no disaggregating effect on the zeolite-concrete cast.

Certain zeolite minerals are routinely added to laundry 

detergents and water softeners. In laundry soaps, zeolite has 

replaced sodium tripolyphosphate, an environmentally harmful 

detergent additive. As a hard water treatment, zeolite reduces 

carbonate deposits in pipes by exchanging insoluble calcium 

and magnesium ions for potassium and sodium ions. The 

sodium and potassium ions are dissolved in the water while 

the calcium and magnesium are extracted and incorporated 

into the zeolite structure.

Zeolite has more uses than can be described in this format. Researchers in the fields of alternative energy, medicine, 

mining, agriculture, environmental safety, hygiene, and even 

pet care continue to discover practical uses for natural and 

synthetic zeolite. It is not surprising, given its unique structure 

and its ion exchange capacity, that zeolite has been called “The 

Magic Rock” (Mumpton, 1999).

Borates

In 1808 the element boron (B) was isolated by Joseph 

Gay-Lussac, a French chemist who documented its chemical 

affinities and physical properties. Nine hundred years before 

Gay-Lussac characterized boron, a compound of the element 

was being used in ceramic glazes and by silversmiths in China 

and Arabia, respectively. The compound was called borax 

(Na2B4O7

.

10H2O, hydrated sodium borate). In 1881 a massive 

borate deposit was discovered in Death Valley, Nev. Two years 

later, the storied 20-mule teams were introduced to the desert 

valley to haul borax from mines to refineries (fig. 17).

Unlike most elements, boron does not exist discretely in 

nature. It is always found in combination with other elements. 

Approximately 80 boron compounds have been identified 

worldwide. Only four boron minerals occur in the United 

States in abundance suitable for mining:

•	 Tincal (pronounced “tinkle,” Na2B4O7

.

10H2O)

•	 Kernite (Na2B4O7

.

4H2O)

•	 Ulexite (sometimes called “bunny tail,” 

NaCaB5O9

.

8H2O)

•	 Colemanite (Ca2B6O11

.

5H2O) (fig.18).

Laboratory studies indicate that these and other borates 

are about as toxic as table salt. The human body does not 

accumulate excess borates. Once ingested or inhaled, the body 

uses what is needed (less than 20 mg per day) and expels 

the remainder. Additionally, borate minerals and the waste 

associated with borate mining are not regulated as irritants, 

toxins, carcinogens, or contaminants for any other organism or 

biotope.

Boron is an essential element in both natural and artificial systems. In nature, boron occurs in soils that formed from 

erosion of borate-bearing rocks. Its presence in a range of soils 

is ideal for most plant populations. As a micronutrient, boron 

contributes to plant reproductive and flowering cycles, pollen 

production, and energy distribution (fig. 19).

In the industrial world borates are used in the manufacture of insulation, fiberglass, and heat-resistant glass. About 43 

percent of annual world borate production goes directly to the 

fiberglass and treated glass industries (IMA, 2003).

An incomplete list of other boron- or borate-containing 

products includes the following: 

•	 Laundry detergents and other cleaning products—

borates are an effective bleaching and stain removal 

agent.

•	 Paint, adhesives, and cosmetics—borates are added 

to these products for their buffering and dispersing 

The Versatile Nine 13

Figure 17. The legendary 20-mule team hauling borax in Death 

Valley, Nev., circa 1890. Photograph Santa Clarita Valley Historic 

Society/SCVHISTORY.com.

______________

1

Adsorb— the accumulation of gases, liquids, or solutes on the surface of 

a solid or liquid. Not to be confused with absorb, which means to take in by 

capillary, osmotic, solvent, or chemical action.
14 Projectile Points and Microprocessors—Influence of Industrial Minerals 

Figure 19. Bright-red Indian paintbrush in Death Valley, Nev., growing amid rocks high in 

borates—boron contributes to flowering cycles. Photograph by author.

Figure 18. Colemanite crystals (dimensions and specimen locale unknown). Photograph 

Stonetrust, Inc., American Geological Institute image library. Image source Earth Science World 

Image Bank http://www.earthscienceworld.org/images.
effect. Borate compounds have the measured capacity 

to balance acidity and alkalinity and to facilitate even 

distribution of disparate ingredients.

•	 Because boron can be adapted as an anti-corrosive, it is 

a primary ingredient in engine additives such as motor 

oil and antifreeze.

•	 Boron fibers, which have a very high tensile strength, 

have been added to plastics to make a material that is 

stronger than steel yet lighter than aluminum. 

•	 When combined with zinc (Zn), borates can be applied 

as flame and smoke retardants.

And finally, because boron is able to absorb neutrons, 

its use has expanded to the field of atomic energy. It is used 

as a construction component of particle detectors and neutron 

shields and as an assimilation element in nuclear reactor rods.

Gypsum

Known to chemists as hydrous calcium sulfate 

(CaSO4

.

2H2O), gypsum has a long history of use. Records 

dating to Greek antiquity describe a transparent mineral used 

to cover temple windows which cast a moon-like light on 

altars. The mineral was named “Selene” after the Greek moon 

goddess. The term continues to this day: the transparent form 

of gypsum is called selenite. Early Mediterranean texts refer 

to a rock called “gypsos,” as do the cuneiform scripts of the 

ancient Assyrians. Modern archeology has identified gypsum 

as a wall dressing in Egyptian pyramids. 

Gypsum is as important a mineral today as it was in the 

distant past. And it is mined and processed today much as 

it was by ancient Greeks and Semites. Mined or quarried, 

gypsum is heated at a relatively low temperature to remove 

water from its structure. This process is called calcination. The 

calcined gypsum is then ground to a fine powder known as 

gypsum stucco, or plaster of Paris. Water is reintroduced to the 

gypsum powder to produce a mortar that can be poured into 

any shaped mold and hardened. Gypsum is the only natural 

substance that can be calcined and then restored to its original 

rock-like state by the addition of water alone.

In the United States today, gypsum deposits are concentrated in two broad, lateral belts. One belt begins in southwest 

Texas and terminates about 1,450 miles away (2,300 kilometers) at the Niagara River in New York State. The other 

extends from California’s Imperial Valley to northern Utah 

(fig. 20). The two gypsum belts supply 90 percent of the U.S. 

wallboard industry (Olson, 2004). Additionally, several million tons of gypsum is imported to the United States each year 

from Nova Scotia and Mexico.

Wallboard, or gypsum board, is one of the most important 

materials in the housing construction industry. The boards 

are formed by sandwiching a core of wet plaster between 

two sheets of paper board. When the core sets and dries, it 

becomes a strong, rigid, fire-resistant building material that 

can be cut to specific dimensions.

In recent years the construction materials industry has 

perfected a gypsum synthesis process that makes use of a 

byproduct of power generation. The sand-sized byproduct is 

collected from the coal desulfurization chambers of power 

plants. It is dewatered, recombined with other elements, rewetted, and then ground into a stucco and sold commercially. 

The synthetic product is chemically and physically comparable to natural gypsum.

Whether naturally occurring or synthesized, gypsum and 

its uses are not restricted to the wall-dressing industry. Gypsum is used as a sanitizing and whitening agent in toothpaste. 

The Versatile Nine 15

Figure 20. View looking north showing badland topography of the Jurassic 

Arapien Shale near Salina, Utah. Gypsum mines are in the center of the 

photograph (light mounds encircled by the road). Photograph by I.J. Witkind, 

1982, USGS Photograph Library (image file wij097cp).
16 Projectile Points and Microprocessors—Influence of Industrial Minerals

238,857

 Miles

Figure 21. A gypsum promenade from the Earth to the Moon, and a gypsum wallboard wall on its way 

around the Earth. Original watercolor illustration by John Driscoll.
It is formed into molds for electrical and mechanical fixtures, 

dental and medical prostheses, and even dinnerware. It is 

also applied to acidic soils as a neutralizing medium. These 

applications, however, account for a very small percentage of 

overall domestic annual use. The yearly production of wallboard used by the U.S. building construction industry is equal 

to a 16-ft wide pathway from the Earth to the Moon or a 275-ft 

wall encircling the entire Earth (fig. 21) or 36 billion square 

feet of material! 

Despite this incredible consumption, gypsum deposits in 

the United States are just about limitless. Since the demand for 

housing and other buildings shows no signs of slacking, it is 

good to know that this particular industrial mineral is abundant 

and relatively inexpensive to extract and process.

Industrial Sand

When we think of sand we think of recreation on sundrenched beaches or vast stretches of shifting, shimmering 

dunes. Rarely do we equate sand with glassmaking, sophisticated electronics, or metallurgy. But glass products and some 

manufacturing processes are indeed dependent on industrial 

silica sand.

Most beaches around the world are accumulations of 

tiny, rounded fragments of such minerals as quartz, feldspar, 

hematite, hornblende, and magnetite. This mixture of mineral grains, while attractive to tourism promoters, is largely 

dismissed by economic geologists who characterize coastal 

beaches as impure sand deposits. Industrial sands, on the other 

hand, are high-purity quartz deposits requiring little in the way 

of processing to remove non-quartz grains.

Industrial sands are most commonly associated with 

inland geologic events involving massive uplift, erosion, and 

active winnowing in stream and lake beds. The natural winnowing, or separation process, occasionally produces ultraclean deposits of silicon dioxide grains (SiO2

), more commonly known as quartz.

Quartz is very hard, it is chemically inert, and it has a 

high melting point. In other words, it is a mineral that can 

withstand moderate impact, does not react with liquids, 

gases, or other solids, and can tolerate extreme temperatures. 

Quartz melts at approximately 1,600°C, at which state, in 

combination with other minerals, it can be rolled or formed 

into flat, durable window glass, sterile containers for food and 

beverages, medical and scientific glassware, and television and 

computer monitor screens. The quality of these glass products 

is determined by the purity of the silica sand—the more pure 

the industrial sand, the better the color, clarity, and strength of 

the glass product made from it.

Like glassmakers, the ferrous and nonferrous foundry 

industries have also made impressive use of fine quartz sand. 

When combined with specific clay minerals (such as bentonite), industrial sand can be shaped into nearly any form from 

engine blocks to faucets. Because silica has an extremely high 

fusion point (the temperature at which a substance becomes 

molten), liquid metal alloys can be poured into silica-clay 

molds without inducing melt. Once the metal is removed 

from the mold, the sand-clay die can be recycled to make new 

molds.

Makers of paints and coatings add high-purity silica to 

their products to improve tint retention, color consistency, and 

weathering resistance.

The construction supply industry in partnership with 

industrial chemists has developed stuccos, epoxy compounds, 

and asphalt mixtures that contain prescribed amounts of industrial sand. This newest generation of construction materials 

promises extended coverage and durability.

For decades, the fossil fuel industry has made specialized use of silica sand. The pumping of pure, well-rounded 

sand into deep wells causes rock fissures and fractures to stay 

propped open, thereby increasing the flow rate of natural gas 

and oil. The structural strength and inherent corrosion resistance of silica sand guarantee its integrity to depths of 8,000 ft 

or more. 

In compound form, silica sand contributes to the production of quality glass, cast metal essentials like machine tools 

and stoves, and long-lasting construction materials. But its 

utility becomes nothing short of astounding when the SiO2

molecule is deconstructed. Using an arc furnace fueled by 

coke (degassed coal), silicon can be separated from oxygen. 

In its reduced form silicon metal is used in the production 

of other beneficial chemical compounds. Examples include 

silicon tetrachloride (SiCl4), a component of semiconductors 

and optic fibers; and water-soluble amorphous sodium silicate 

(Na2O.xSiO2), an egg preservative. (Eggs are dipped in an 

aqueous sodium silicate solution; when dry, the solution forms 

a bacteria barrier around the eggshell, preserving the freshness 

of the egg for months.)

Just as silicon can be separated from oxygen, it can also 

be chemically synthesized, or cultured, for use in the electronics industry (fig. 22). Advanced microcircuits, frequency 

controls, and timers all require integrated silicon grains, nearly 

all of which are manmade. 

Clearly, industrial sand (known in industry as silica sand 

or high-purity quartz) is a crucial element of everyday life. It 

is present in our double-pane windows and our glossy paints. 

It facilitates medical research and voice and image transmission. And, believe it or not, it is even lurking in those sinister 

bunkers on the golf course (fig. 23). 

Talc

Talc is a very soft mineral, the softest on the Mohs 

scale.2 Talc varies in color from pale green to yellowish white 

The Versatile Nine 17

2

The Mohs scale is a mineral identification system based on comparative 

hardness. The scale lists 10 minerals in order from 1-softest (talc) to 10-hardest (diamond). The system was developed by Friedrich Mohs, an 18th century 

German mineralogist.

_____________
18 Projectile Points and Microprocessors—Influence of Industrial Minerals

Figure 22. Synthetic silicon crystal measuring 3x3x3 in. Photograph by author.

Figure 23. A snow-rimmed sand bunker, public golf course. Photograph by author.
to bright white. It is generally flaky or scaly in appearance 

and always slippery to the touch. Referred to by chemists as 

hydrous magnesium silicate, talc has the chemical formula 

Mg3Si4O10(OH)2. In pure form, talc is 63.5 percent SiO2

(silicon dioxide), 31.7 percent MgO (magnesium oxide), 

and about 5 percent water. Talc rarely occurs in pure form 

in nature. It is most often intergrown with chlorite, epidote, 

diopside, and (or) tremolite. Mine operators and end-users 

describe talc as one or the other of the following:

•	 Steatite—a fine-grained, massive, compact form 

•	 Soft, platy—considered the most commercial form of 

talc; at least 90 percent of the world’s talc deposits are 

of the soft and flaky variety 

•	 Tremolite talc—usually occurring as a massive or laminated (thin layers) rock consisting of intergrowths of 

tremolite (Ca2Mg5Si8O22(OH)2) and talc and the accessory minerals anthophyllite ((Mg,Fe)7

Si8O22(OH)2), 

calcite (CaCO3), and dolomite (CaMg(CO3)

2

) 

•	 Mixed talc—any type of talc that is of moderate to low 

purity and (or) growing in combination with oxide 

minerals such as hematite and magnetite. Mixed talc is 

commonly known as “soapstone.”

Large active talc mines are located in Montana (the 

largest producer), Texas, Vermont, and upstate New York 

(tremolitic talc). The former two deposits are characterized as 

dense microcrystalline ores, meaning individual talc crystals 

are only visible with the aid of a microscope. Macro, or mega, 

crystals—those which are visible to the unaided eye—are 

mined in northern Vermont and upstate New York. In general, the macrocrystalline talcs contain a higher percentage 

of impurities than the microcrystalline species and require 

froth flotation refinement. Froth flotation is a process used 

to separate the desired mineral (talc) from gangue, or waste 

rock (tremolite or dolomite, for example). First, the ore is 

crushed into a fine powder and then conveyed to a bulk liquid 

containing an organic surfactant. The surfactant, similar to a 

detergent, reduces the surface tension of the liquid and enables 

upward movement, or flotation, of talc grains. As grains accumulate at the surface of the bulk liquid, they are scraped into 

a clean, aerated water bath. There, the fine talc grains attach 

to air bubbles and rise in columns to form a froth on the bath 

surface. The froth is pumped off and analyzed for purity.

In addition to being size-specific, industrial applications are also type-specific. For example, the very finest talcs, 

produced by advanced milling technology, are essential to the 

polypropylene (light, conformable plastic) industry—makers of automotive dashboards and bumpers. The stiffness and 

stability of these molded components are due in large part to a 

thermoplastic recipe that includes exceptionally clean microcrystalline talc.

The coatings industry is another major consumer of the 

fine, platy variety of talc. Marine and automotive primers and 

topcoats, traffic paints, powder coatings, crack fillers, and 

caulks consume about 180,000 short tons of soft talc each year 

(Ciullo and Robinson, 2003). Adding platy talc to coating 

compounds markedly improves dispersion and brushability, as 

well as crack, rupture, and corrosion resistance. Microcrystalline talc is structured like the scales of a fish—aligned and 

overlapping—forming a nearly impenetrable barrier to humidity or water, the common causes of coating “blisters,” cracks, 

and discoloration (fig. 24).

Tremolitic talcs also have their place in coating manufacturing. Coarser than platy talcs, tremolite talcs offer greater 

scrub resistance and increased light-scatter for a high gloss 

finish. In addition to its utility in paints and surface coatings, 

tremolite talc is a mineral component of floor and wall tiles, 

sanitary ware, and ceramic glazes.

In the paper industry mixed talc is used to extract resinous particles from pulps and residue ink from recycled paper. 

High-speed printing processes rely on paper that has been 

treated with low-purity talc to eliminate surface friction.

Natural steatite, because it occurs as massive bodies, is 

often quarried for the production of statuary and other carved 

objects. Aside from its esthetic value, this fine-grained talc 

is used by the electronics and pharmaceutical industries. The 

former has developed a steatite-alumina compound that can 

be pressed into cellular phone components, thermostats, and 

semiconductor devices. Drug makers use only pure-grade 

steatite as a pill additive and preservative.

And finally, bubble blowers everywhere must appreciate talc for the nonstick nature of gum, and fashion-conscious women (and men) for the sheen and transparency 

of cosmetics.

Stone Products—Aggregate, Dimension Stone, 

and Abrasives

An essential and frequently overlooked industrial mineral 

is known collectively as coarse or natural aggregate. Coarse 

aggregate is generally described as nonmetallic, nonfuel rock 

fragments, which include gravel, crushed stone, and sand (fig. 

25). Gravel is defined as naturally occurring rounded rock 

particles of a size ranging from 3/

16 in. to 3 in. Crushed stone 

is a manufactured product usually obtained by the crushing 

of bedrock, boulders, cobbles, or gravel. Sand is smaller than 

gravel, but larger than silt and clay.

So, why would unassuming rock fragments rank as one 

of the most important industrial minerals? The answer is that 

aggregate is the literal foundation of our homes and offices, 

roadways and runways, bridges, dams, and rail lines (fig. 26). 

This unspectacular material is the fundamental component 

of water and sewage filtration systems. It is used to reshape, 

rehabilitate, and conserve landscapes. Without aggregate 

there would be no high-speed transportation networks, no 

on-demand clean tap water, no reclaimed open spaces or urban 

walking trails, and no convenient buildings in which to work, 

play, learn, or sleep.

The Versatile Nine 19 
20 Projectile Points and Microprocessors—Influence of Industrial Minerals

Figure 24. Scanning electron microscope (SEM) images of microcrystalline talc crystals. Courtesy of B.S. Van Gosen.

Figure 25. Pebbles, coarse sand, and gravel (left to right). Red sandstone slab 

measures 24 in. long. Photograph by author.
Figure 26. Uses and production of aggregate. Top, train rails with crushed stone substructure. Middle, heavily trafficked 

concrete overpass. Bottom, aggregate mining and processing near Saratoga, Wyo. Photographs by author.

The Versatile Nine 21
22 Projectile Points and Microprocessors—Influence of Industrial Minerals

Figure 27. Uses of aggregate abrasive. Top, horizontal grinder with replaceable abrasive wheel. Middle, belt sander. Bottom, very 

coarse sanding strip. Photographs by author.

 
Aggregate, like other industrial minerals, is mined or 

quarried. First, a sizable deposit of strong, weather-resistant 

aggregate is located, then mining permits are approved by 

local, State, or Federal government authorities, and finally, 

drilling, blasting, loading, crushing, and screening commence 

at the deposit site. From the mine, specific sized aggregate is 

hauled by truck, train, or barge to a road construction project 

where it is spread as the stabilizing under-layer of a paved 

highway or residential street; to a concrete plant where it is 

mixed with cement and subsequently poured as surface pavement or a building foundation; to a municipal water treatment 

plant to be incorporated in a through-flow filtering system; 

to a retaining structure or airport runway needing repair; to a 

bridge reinforcement or erosion control project; or to a redevelopment site where it is layered on by the ton. The vitality 

of commerce, cities, and neighborhoods depends on natural 

coarse aggregate.

Not all natural stone products are aggregates. A special 

type of stone called dimension stone is sometimes quarried for 

decorative use. Slabs of granite, dolomite, marble, and slate 

are the preferred rock for exterior and interior wall dressings, 

countertops, and floors. In its unfinished state dimension stone 

is interesting and attractive. But its real beauty is apparent only 

after it has been polished—tiny fossilized creatures or distinctive minerals are revealed in the matrix of the stone. 

To obtain a polished finish, another type of stone, known 

as abrasives, is employed. Abrasive aggregates are extremely 

hard, fine mineral particles. They include iron oxides and 

corundum, industrial garnets and diamonds. These abrasive 

minerals are bonded to cutters and grinders, or imbedded in 

cloth or heavy paper (fig. 27). Every commercial and amateur 

fabricator and refurbisher who produces a clean cut or fine 

smooth finish owes his or her handiwork to industrial aggregate of the abrasive kind.

There can be no doubt that use of aggregate and other 

stone products contributes to affluence and comfort. Paved 

roads and reliable rail lines make possible a constant supply 

of fuel and food. Dirt roads, by contrast, can be punishing and 

unpredictable. A filtered municipal water supply guarantees 

potability. Unfiltered, untreated water assures microbial disease. Acts of nature can level a village built of wood, but stone 

buildings can withstand fire and flood. 

Imagine for a moment the terraced, irrigated slopes of 

the ancient Ecuadoran Imaru people,3 or the precise roads and 

aqueducts of early Rome. Imagine also the castle fortresses of 

the Celtic Golden Age and the engineered harbor of long-ago 

Alexandria—people and places as different as copper and 

coconuts, yet the same in one respect: their practical use of 

stone, the natural resource that fostered social stability, political continuity, assimilation, and economic expansion. Many of 

the standing stone structures built by these and other venerable peoples remind us that aggregate is the industrial mineral 

that has had the greatest effect on history: the one material 

that since ancient time has separated the primitive from the 

progressive.

So, the next time you see a pile of nondescript rocks, 

think about snug dwellings, safe landings, and the roads you 

travel.

Final Words

Driving west on Interstate 70 over the Colorado Rockies, motorists are reminded of the mining history of the 

region—those heady days of gold and silver that beckoned the 

adventurer. Long-ago laughter and piano music, gun shots and 

galloping hooves can be heard on the mountain wind now and 

then. Those were the good old days of hard rock, hard labor, 

and hard drinking. There wasn’t anything soft in the life of a 

19th century miner. The roads in town or up the mountain had 

two seasons—dust or mud. Parasites lived in the water supply 

necessitating boiling beforehand. Clothes were laundered in 

caustic lye. A scarcity of toothpaste meant rotten teeth. Communication was a hard ride on a hard road. Neither cardboard 

nor oil cloth kept the wind or wet or cold from the chinked 

cabin interior. Commodes were a brass pot or a hole in the 

ground. Pain relievers were sold without a guarantee of purity. 

The air in camp was grimy with wood smoke or coal dust. And 

food production was only as good as the soil or the fodder that 

sustained it. Though few prospectors found the motherlode, 

many would have found consolation in clean water, window 

glass, fiber insulation, and guaranteed pain remedies. The 

real hardships of the 19th century prospector’s life are all but 

forgotten in many parts of the 21st century world—a world of 

shatterproof glass, long-lasting pavement, purified water, and 

emission scrubbers; a world made comfortable and predictable 

by amazing industrial minerals.

Selected References 

About..., accessed July 6, 2004 at URL http://www.chemistry.

about.com.

ASTM International, 2004, C494/C494M-04 Standard specification for chemical admixtures for concrete: Accessed 

March 12, 2004 at URL http://www.cement.org.

Ciullo, P.A., and Robinson, S., 2003, Talc—Shape and 

form meet function: Accessed May 22, 2004 at URL 

http://www.pcimag.com.

Selected References 23

3

The Andes Mountains (Imaru highlands) trend north-south through the 

center of Ecuador.

____________
24 Projectile Points and Microprocessors—Influence of Industrial Minerals

Davis, W.S., 1912, Readings in ancient history—Illustrative 

extracts from the sources, Two Volumes: Boston, Mass., 

Allyn and Bacon, Volume II, Rome and the West, p. 

215–222.

Dexter, A.R., 1998, Advances in characterization of soil structures: Soils and Tillage Research, p. 199–238.

Goldman, H.B., 1994, Sand and gravel, in Carr, D.D., ed., 

Industrial minerals and rocks, Sixth Edition: Society for 

Mining, Metallurgy, and Exploration, Inc., p. 869–877.

Houk, C.C., and Post, R., 1996, Chemistry—Concepts and 

problems—A self-teaching guide: New York, John Wiley, 

384 p.

IMA (Industrial Minerals Association)—North America, 

2003, Borates: Accessed February 12, 2004 at URL http://

www.ima-na.org. 

Knepper, D.H., ed., 2002, Planning for the conservation and 

development of infrastructure resources in urban areas—

Colorado Front Range Urban Corridor: U.S. Geological 

Survey Circular 1219, 32 p.

Langer, W.H., 1988, Natural aggregates of the conterminous 

United States: U.S. Geological Survey Bulletin 1594, 33 p.

Mumpton, F.A., ed., 1981, Special zeolite issue: Clays and 

Clay Minerals, v. 29, no. 5, 212 p. 

Mumpton, F.A., 1999, La Roca Magica—Uses of natural zeolites in agriculture and Industry: Proceedings of the National 

Academy of Sciences, v. 96, p. 3465–3470.

Murphy, J.A., 1997, Geology tour of Denver’s Capitol Hill 

stone buildings: Historic Denver, Inc., 96 p.

NAWC (North American Weather Consultants, Inc.), 2003, 

Cloud seeding—Weather modification: Accessed December 

10, 2003 at URL http://nawc@nawcinc.com.

Noe, D.C., 1997, A guide to swelling soils for Colorado 

homebuyers and homeowners: Colorado Geological Survey 

Special Publication, 76 p.

Olson, D.W., 2004, Gypsum: U.S. Geological Survey Mineral 

Commodity Summaries 2004, p. 76.

Portland Cement Association, 2004, Accessed March 15, 2004 

at URL http://www.cement.org. 

Shacklette, H.T., and Boerngen, J.G., 1984, Element concentrations in soils and other surficial materials of the conterminous United States: U.S. Geological Survey Professional 

Paper 1270, 105 p.

 

Sharp, R.P., and Glazner, A.F., 1997, Geology underfoot in 

Death Valley and Owens Valley: Missoula, Mont., Mountain 

Press Publishing Company, 319 p.

Smallwood, C.L., Lipscomb, J., Swartout, J., and Tueschler, 

L., 2004, Toxicological review of boron and compounds: 

U.S. Environmental Protection Agency IRIS 7440-42-8, 

134 p. 

Swarm, L., and Fitzgerald, S., 1992, Use and application of 

salt in aquaculture: North Central Regional Aquaculture 

Center, Publication 105, 2 p.

Tepordei, V.V., 1997, Natural aggregates—Foundation of 

America’s future: U.S. Geological Survey Fact Sheet 

FS-144-97, 4 p. 

U.S. Department of Agriculture, 1969, Handbook No. 60—Diagnosis and improvement of saline and alkali soils: U.S. 

Department of Agriculture Special Publication, available on 

the Web at http://www.ussl.ars.usda.gov.

U.S. Environmental Protection Agency, 1995, EPA Office of 

Compliance Sector Notebook Project—Profile of the nonfuel, non-metal mining industry: EPA 310-R-95-011, 6 p.

U.S. EPA (Environmental Protection Agency), 1998, Zeolite—A versatile air pollutant adsorber: EPA Technical 

Bulletin 456/F-98-004, p. 7.

U.S. Geological Survey, 1998, Front Range Infrastructure 

Resources Project—Aggregate resources activities: U.S. 

Geological Survey Fact Sheet FS-119-98, 4 p.

U.S. Geological Survey, 2000, Nitrogen in the Mississippi 

Basin—Estimating sources and predicting flux to the Gulf 

of Mexico: U.S. Geological Survey Fact Sheet FS-135-00, 

2 p.

U.S. Geological Survey, 2000, U.S. talc—Baby powder and 

much more: U.S. Geological Survey Fact Sheet FS-0065-00, 

2 p.

U.S. Geological Survey, 2004, Mineral commodity summaries, 

2004: Accessed July 7, 2004 at URL http://minerals.er.usgs.

gov/minerals/pubs/mcs/2004.

van Oss, H.G., 2004, Cement: U.S. Geological Survey Mineral 

Commodity Summaries 2004, p. 42.
Appendix 25

 Appendix. Domestic and World Production of Industrial Minerals

Industrial 

mineral

Domestic production

in thousand or million 

metric tons

(t, thousand; m, million)

Domestic active 

quarries, pits, 

mines

 Average price

U.S. dollars per metric 

ton

Employment

Total value 

(raw)

U.S. dollars

2002 2003 2003 2002 2003 2002 2003 2003

Bentonite 3,970 (t) 3,970 (t) 760 (p) 45 45 6,550 6,400 $1.6 billion

Borates 518 (t) 536 (t) 4 (p) 359 Not 

available 1,300 1,300 275 million

 Crushed

 stone

1,520

(m) 1,490 (m) 3,330 (q) 5.71 5.78 79,000 78,000 8.6 billion

 Dimension

 stone 1,260 (t) 1,350 (t) 176 (q)

Variable. 

Depends 

on type of 

product

Variable. 

Depends 

on type of 

product

1,500 1,500 236 million

 Sand and

 gravel

1,130

(m) 1,130 (m) 6,400 (q, p) 5.07 5.14 35,300 35,300 5.8 billion

Gypsum 

(crude)

15,700

(m) 16,000 (m) 50 (m) 6.9 6.9 5,900 5,900 111 million

Industrial sand

Domestic 

mining and 

processing 

ended in 

1997

Not 

applicable

U.S. 100% 

import reliant

Variable.

Depends on 

country of 

origin 

Variable.

Depends on 

country of 

origin 

Employment 

figures 

unavailable

Employment 

figures 

unavailable

Total value 

unavailable for 

2003

 Refined 

silicon 261 (t) 250 (t) 4 (laboratory process) 41.1 49

Employment 

figures 

unavailable 

Employment 

figures 

unavailable

307 million

Portland 

cement

91,300

(t) 92,600 (t) 116 (plants) 76 76 18,100 18,100 8.3 billion

Salt 40,300

(t) 41,200 (t) 69 (m, solar) 120.02 122 4,100 4,100 1 billion

Talc 775 (t) 817 (t) 9 (m) 96 114 510 500 19 million

*Zeolite 36.4 (t2001) 46 (t-2003) 9 (p, m) 60-320 

 (2001)

Not 

available 

Employment 

figures 

unavailable

Employment 

figures 

unavailable

Total value 

unavailable for 

2003

Data based on U.S. Geological Survey Mineral Commodity Summaries, 2004, http://minerals.er.usgs.gov/minerals/pubs/mcs/2004.

*Data provided by Robert L. Virta, U.S. Geological Survey, Reston, VA, March 2004.
26 Projectile Points and Microprocessors—Influence of Industrial Minerals

Industrial 

mineral

World production excluding U.S. in thousand 

metric tons (t, thousand) Principal countries of production outside U.S.

2002 2003

Bentonite 6,030 (t) 6,130 (t) Brazil, Czech Republic, Germany, Greece, Italy, 

 Mexico, Turkey

Borates 3,530 (t) 3,290 (t) Argentina, Bolivia, Chile, People’s Republic of China, Russia,

 Turkey, Iran, Peru

Crushed 

stone, sand, 

and gravel

 15 billion metric tons Large Most developed countries

Dimension 

stone

 Sufficient Sufficient Italy, Canada, India, Spain, Brazil

Gypsum 85,300 (t) 86,000 (t) Iran, Canada, People’s Republic of China, Thailand, Spain, 

 Japan, Australia

Refined 

silicon 3,459 (t) 3,750 (t) People’s Republic of China, Russia, Ukraine, Brazil, France,  Norway

Portland 

cement 1,708,700 (t) 1,767,400 (t) People’s Republic of China, India, Japan, Republic of Korea,  Brazil, Indonesia, Turkey

Salt 169,700 (t) 168,800 (t) People’s Republic of China, Canada, India, Germany, Australia, 

 Poland, United Kingdom

Talc 8,095 (t) 8,043 (t) People’s Republic of China, Republic of Korea, Japan, India, 

 Brazil

Zeolite approximately 2,736,500

 metric tons (2001)

Data not 

available

People’s Republic of China, Japan, Cuba, Hungary, Slovakia, 

 Georgia, New Zealand, Greece

Data based on U.S. Geological Survey Mineral Commodity Summaries, January 2004, http://minerals.er.usgs.gov/minerals/pubs/mcs/2004.