ANHYDRITE | Increasing importance as a fertilizer, and in manufacture of plasters, cements, sulfates, and sulfuric acid | ANHYDRITE | CaSO4 | 2.95 | An important gangue mineral in porphyry Cu–Mo deposits. Occurs with gypsum and halite as a saline residue. Occurs also in “cap rock” above salt domes, and as minor gangue mineral in hydrothermal metallic ore veins |
APATITE | See Phosphates | | | | |
ASBESTOS | Heat-resistant materials, such as fire-proof fabrics and brake-linings. Also asbestos cement products, sheets for roofing and cladding, fire-proof paints, etc. | | | | Group of six minerals with same habit, roughly 1:20 aspect ratio, thin fibrous crystals |
CHRYSOTILE (Serpentized asbestos) | Mg3Si2O5(OH)4 | 2.5–2.6 | Fibrous serpentine occurring as small veins in massive serpentine |
CROCIDOLITE | Na2(Mg,Fe,Al)5Si8O22(OH)2 | 3.4 | Fibrous riebeckite, or blue asbestos, occurring as veins in bedded ironstones |
AMOSITE | (Mg,Fe)7Si8O22(OH)2 | 3.2 | Fibrous grunerite, occurring as long fibers in certain metamorphic rocks |
ACTINOLITE | Ca2(Mg,Fe)5Si8 O22(OH)2 | 3.0–3.4 | Occurring in schists and in some igneous rocks as alteration product of pyroxene |
BADDELEYITE | Ceramics, abrasives, refractories, polishing powders, and manufacture of zirconium chemicals | BADDELEYITE | ZrO2 | 5.4–6.0 | Mainly found in gravels with zircon, tourmaline, corundum, ilmenite, and rare-earth minerals |
BARYTES | Main use in oil- and gas-well drilling industry in finely ground state as drilling muds. Also in manufacture of barium chemicals, and as filler and extender in paint and rubber industries | BARYTE | BaSO4 | 4.5 | Most common barium mineral, occurring in vein deposits as gangue mineral with ores of lead, copper, zinc, together with fluorite, calcite, and quartz. Also as replacement deposit of limestone and in sedimentary deposits |
BORATES | Used in manufacture of insulating fiberglass, as fluxes for manufacture of glasses and enamels. Borax used in soap and glue industries, in cloth manufacture and tanning. Also used as preservatives, antiseptics, and in paint driers | BORAX | Na2B4O5(OH)4·8H2O | 1.7 | An evaporate mineral, precipitated by the evaporation of water in saline lakes, together with halite, sulfates, carbonates, and other borates in arid regions |
KERNITE | Na2B4O6(OH)2·3H2O | 1.95 | Important source of borates. Occurrence as for borax |
COLEMANITE | Ca2B6O11·5H2O | 2.4 | In association with borax, but principally as a lining to cavities in sedimentary rocks |
ULEXITE | NaCaB5O6 (OH)6·5H2O | 1.9 | Occurs with borax in lake deposits. Also with gypsum and rock salt |
SASSOLITE | H3BO3 | 1.48 | Occurs with sulfur in volcanoes and in hot lakes and lagoons |
BORACITE | Mg3B7O13Cl | 2.95 | Occurs in saline deposits with rock-salt, gypsum, and anhydrite |
CALCIUM CARBONATE | Many uses according to purity and character. Clayey variety used for cement, purer variety for lime. Marble for building and ornamental stones. Used as smelting flux, and in printing processes. Chalk and lime applied to soil as dressing. Transparent calcite (Iceland spar), used in construction of optical apparatus | CALCITE | CaCO3 | 2.7 | Common and widely distributed mineral, often occurring in veins, either as main constituent, or as gangue mineral with metallic ores. It is a rock-forming mineral, which is mainly quarried as the sedimentary rocks limestone and chalk, and metamorphic rock marble |
CHINA CLAY | Manufacture of porcelain and china. Used as filler in manufacture of paper, rubber, and paint | KAOLINITE | Al2Si2O5(OH)4 | 2.6 | A secondary mineral produced by the alteration of aluminous silicates, and particularly of alkali feldspars |
CHROMITE | Used as refractory in steel-making furnaces | See CHROMIUM (Appendix I) |
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CORUNDUM |
Abrasive. Next to diamond, hardest known mineral. Colored variety used as gemstones |
CORUNDUM |
Al2O3 |
3.9–4.1 |
Original constituent of various igneous rocks, such as syenite. Also in metamorphic rocks such as marble, gneiss, and schist; and in pegmatites and alluvial deposits. Impure form is emery, containing much magnetic and hematite |
CRYOLITE |
Used as flux in manufacture of aluminum by electrolysis |
CRYOLITE |
Na3AlF6 |
3.0 |
Occurs in pegmatite veins in granite with siderite, quartz, galena, sphalerite, chalcopyrite, fluorite cassiterite, and other minerals. Only significant deposit in Greenland |
DIAMOND |
Gemstone. Used extensively for abrasive and cutting purposes—hardest known mineral. Used for tipping drills in mining and oil industry |
DIAMOND |
C |
3.5 |
Distributed sporadically in kimberlite pipes. Also in alluvial beach and river deposits. Bort refers to shards of non-gem-grade diamonds, used industrially |
DOLOMITE |
Important building material. Also used for furnace linings and as flux in steel-making |
DOLOMITE |
CaMg(CO3)2 |
2.8–2.9 |
Rock-forming mineral. Occurs as gangue mineral in veins containing galena and sphalerite |
EMERY |
See CORUNDUM |
| | | |
EPSOM SALTS |
Medicine and tanning |
EPSOMITE |
MgSO4·7H2O |
1.7 |
Usually as encrusting masses on walls of caves or mine workings. Also in oxidized zone of pyrite deposits in arid regions |
FELDSPAR |
Used in manufacture of porcelain, pottery, and glass. Also in production of glazes on earthware, etc., and as mild abrasive |
ORTHOCLASE (Isomorphous forms—Microline, Sanidine, and Adularia—the potassic feldspars) |
KAlSi3O8 |
2.6 |
Most abundant of all minerals, and most important rock-forming mineral. Widely distributed, mainly in igneous, but also in metamorphic and sedimentary rocks |
ALBITE |
NaAlSi3O8 |
2.6 |
| | ANORTHITE |
CaAl2Si2O8 |
2.74 |
|
(Plagioclase feldspars form series having formulae ranging from NaAlSi3O8 to CaAl2Si2O8, changing progressively from albite, through oligoclase, andesine, labradorite, and bytownite to anorthite) |
FLUORSPAR |
Mainly as flux in steelmaking. Also for manufacture of specialized optical equipment, production of hydrofluoric acid, and fluorocarbons for aerosols. Color-banded variety known as Blue-John used as semi-precious stone |
FLUORITE |
CaF2 |
3.2 |
Widely distributed, hydrothermal veins and replacement deposits, either alone, or with galena, sphalerite, barytes, calcite, and other minerals |
GARNET |
Mainly used as abrasive for sandblasting of aircraft components, and for wood polishing. Also certain varieties used as gemstones |
PYROPE |
Mg3Al2(SiO4)3 |
3.7 |
Widely distributed in metamorphic and some igneous rocks. Also commonly found as constituent of beach and river deposits. Andradite is an important mineral in skarns where it may be accompanied by chalcopyrite, spalerite, and galena |
ALMANDINE |
Fe3Al2(SiO4)3 |
4.0 |
GROSSULAR |
Ca3Al2(SiO4)3 |
3.5 |
ANDRADITE |
Ca3Fe2(SiO4)3 |
3.8 |
SPESSARTITE |
Mn3Al2(SiO4)3 |
4.2 |
UVAROVITE |
Ca3Cr2(SiO4)3 |
3.4 |
GRAPHITE (Plumbago) |
Manufacture of foundry molds, crucibles, and paint; used as lubricant and as electric furnace electrodes |
GRAPHITE |
C |
2.1–2.3 |
Occurs as disseminated flakes in metamorphic rocks derived from rocks with appreciable carbon content. Also as veins in igneous rocks and pegmatites |
GYPSUM |
Used in cement manufacture, as a fertilizer, and as filler in various materials such as paper, rubber, etc. Used to produce plaster of Paris |
GYPSUM |
CaSO4·2H2O |
2.3 |
Evaporate mineral, occurring with halite and anhydrite in bedded deposits. Can occur as a gangue mineral in volcanogenic massive sulfide deposits of Cu, Pb, and Zn |
ILMENITE |
About 90% of ilmenite produced is used for manufacture of titanium dioxide, a white compound used as a pigment and as a sunscreen agent |
See TITANIUM (Appendix I) |
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MAGNESITE |
Used as refractory for steel furnace linings, and in production of carbon dioxide and magnesium salts |
See MAGNESIUM (Appendix I) |
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MICA |
Used for insulating purposes in electrical apparatus. Ground mica used in production of roofing material, and in lubricants, wall-finishes artificial stone, etc. Powdered mica gives “frost” effect on Christmas cards and decorations |
MUSCOVITE |
KAl2(AlSi3O10)(OH,F)2 |
2.8–2.9 |
Widely distributed in igneous rocks, such as granite and pegmatites. Also in metamorphic rocks—gneisses and schists. Also in sedimentary sandstones, clays, etc. |
PHLOGOPITE |
KMg3(AlSi3O10)(OH,F)2 |
2.8–2.85 |
Most commonly in metamorphosed limestones, also in igneous rocks rich in magnesia |
BIOTITE |
K(Mg,Fe)3(AlSi3O10)(OH,F)2 |
2.7–3.3 |
Widely distributed in granite, syenite and diorite. Common constituent of schists and gneisses and of contact metamorphic rocks |
PHOSPHATES |
Main use as fertilizers. Small amounts used in production of phosphorous chemicals |
APATITE |
Ca5(PO4)3(F, Cl, OH) |
3.1–3.3 |
Occurs as accessory mineral in wide range of igneous rocks, such as pegmatites. Also in metamorphic rocks, especially metamorphosed limestones and skarns. Principal constituent of fossil bones in sedimentary rocks. Other important phosphates are monazite and xenotime commonly associated with rare earth minerals and may be enriched in REE (See RARE EARTHS in Appendix I) |
PHOSPHATE ROCK |
Complex phosphates of Ca, Fe, A1 |
| Most extensive phosphate rock deposits associated with marine sediments, typically glauconite-bearing sandstones, limestones, and shales. Guano is an accumulation of excrement of sea-birds, found mainly on oceanic islands |
POTASH |
Used as fertilizers, and source of potassium salts. Nitre also used in explosives manufacture (saltpetre) |
SYLVITE |
KC1 |
2.0 |
Occurs in bedded evaporate deposits with halite and carnallite |
CARNALLITE |
KMgCl3·6H2O |
1.6 |
In evaporate deposits with sylvite and halite |
ALUNITE |
KAl3(SO4)2(OH)6 |
2.6–2.9 |
Secondary mineral found in areas where volcanic rocks containing potassic feldspars have been altered by acid solutions |
NITRE |
KNO3 |
2.1 |
Occurs in soils in arid regions, associated with gypsum, halite, and nitratine |
QUARTZ |
Building materials, glass making, pottery, silica bricks, ferro-silicon, etc. Used as abrasive in scouring soaps, sandpaper, toothpaste, etc. Due to its piezo-electric properties, quartz crystals widely used in electronics |
See SILICON (Appendix I) |
| | |
ROCK SALT |
Culinary and preservative uses. Wide use in chemical manufacturing processes |
HALITE |
NaCl |
2.2 |
Occurs in extensive stratified evaporate deposits, formed by evaporation of land-locked seas in geological past. Associates with other water soluble minerals, such as sylvite, gypsum, and anhydrite |
RUTILE |
Production of welding rod coatings, and titanium dioxide. High refractive index makes it useful for manufacture of certain optical elements |
See TITANIUM (Appendix I) |
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SERPENTINE |
Used as building stone and other ornamental work. Fibrous varieties source of asbestos (See ASBESTOS) |
LIZARDITE |
Mg3Si2O5(OH)4 |
2.55–2.6 |
The most common serpentine mineral. Typically a product of retrograde metamorphism, replacing olivine, orthopyroxene, or other minerals in ultramafic igneous rocks |
| | ANTIGORITE |
(Mg,Fe)3Si2O5(OH)4 |
2.5–2.6 |
Widespread, less common than lizardite. Found in regional and contact metamorphosed serpentinites. Associated with chromite, magnetite, chrysotile, olivine |
CHRYSOTILE |
Mg3Si2O5(OH)4 |
| Most commonly encountered form of asbestos. Naturally occurring fiber bundles |
SILLIMANITE |
Raw material for high-alumina refractories, for iron and steel industry, and other metal smelters. Also used in glass industry, and as insulating porcelains for spark-plugs, etc. |
KYANITE (Disthene) |
Al2SiO5 |
3.5–3.7 |
Typically in regionally metamorphosed schists and gneisses, together with garnet, mica, and quartz. Also in pegmatites and quartz veins associated with schists and gneisses |
ANDALUSITE |
Al2SiO5 |
3.1–3.2 |
In metamorphosed rocks of clayey composition. Also as accessory mineral in some pegmatites, with corundum, tourmaline, and topaz |
SILLIMANITE |
Al2SiO5 |
3.2–3.3 |
Typically in schists and gneisses produced by high-grade regional metamorphism |
MULLITE |
Al6Si2O13 |
3.2 |
Rarely found in nature, but synthetic mullite produced in many countries |
SULFUR |
Production of fertilizers, sulfuric acid, insecticides, gunpowder, sulfur dioxide, etc. |
NATIVE SULFUR |
S |
2.0–2.1 |
In craters and crevices of volcanoes. In sedimentary rocks, mainly limestone in association with gypsum. Also in cap rock of salt domes, with anhydrite, gypsum, and calcite |
PYRITE |
See IRON (Appendix I) |
|
TALC |
As filler for paints, paper, rubber, etc. Used in plasters, lubricants, toilet powder, French chalk. Massive varieties used for sinks, laboratory tabletops, acid tanks, etc. |
TALC |
Mg3Si4O10(OH)2 |
2.6–2.8 |
Secondary mineral formed by alteration of olivine, pyroxene, and amphibole, and occurs along faults in magnesium-rich rocks. Also occurs in schists, in association with actinolite. Massive talc known as soapstone or steatite |
VERMICULITE |
Outstanding thermal and sound insulating properties, light, fire-resistant, and inert—used principally in building industry |
VERMICULITE |
Mg3(Al, Si)4O10(OH)2·4H2O |
2.3–2.7 |
Occurs as an alteration product of magnesian micas, in association with carbonatites |
WITHERITE |
Source of barium salts. Small quantities used in pottery industry |
WITHERITE |
BaCO3 |
4.3 |
Not of wide occurrence. Sometimes accompanies galena in hydrothermal veins, together with anglesite and barite |
ZIRCON SAND |
Used in foundries, refractories, ceramics, and abrasives, and in chemical production |
See ZIRCONIUM (Appendix I) |
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