Minerals
Amphibole
Amphibole defines an important group of dark-colored rock-forming inosilicate minerals composed of double chain SiO4 tetrahedra linked at the vertices and generally containing ions of iron and/ or magnesium in their structures. In chemical composition ...
Aragonite
Aragonite is a polymorph of the mineral calcite, both having the chemical composition CaCO3. Its structure differs from calcite and leads to a different crystal shape, an orthorhombic system with acicular crystals. By repeated twinning pseudo-hexagonal...
Asbestos
Asbestos (Greek a-, "not"; sbestos, "extinguishable") is a group of fibrous metamorphic minerals. The name is derived for its historical use in lamp wicks; the resistance of asbestos to fire has long been exploited for a variety of purposes. It was use...
Augite
Augite is a mafic mineral described chemically as (Ca, Na)(Mg, Fe, Al)(Al, Si)2O6 or calcium sodium magnesium iron aluminium silicate. Structurally, it is a solid solution of the pyroxene group which also contains diopside and hedenbergite. The crystal...
Aurichalcite
Aurichalcite is a mineral, usually found as a secondary mineral in copper and zinc deposits. Its chemical formula is (Zn,Cu)5(CO3)2(OH)6. The name probably originates from the Greek oreichalchos meaning "mountain copper".
Autunite
Autonite (Hydrated Calcium Uranyl Phosphate) is a yellow - greenish fluorescent mineral with a Hardness of 2 - 2½. Due to the high content in uranium, it is radioactive and also used as uranium ore. If the mineral dries out, it converts to meta-autu...
Azurite
Azurite is a carbonate mineral with chemical composition Cu3(CO3)2(OH)2, (copper carbonate hydroxide). Azurite is often found in association with the green mineral malachite as a result of the weathering and oxidation of copper sulfide minerals. The...
Barite
Barite (BaSO4) is a mineral consisting of barium sulfate. It is generally white or colorless, and is the main source of barium. Baryte is the British spelling. The radiating form is also sometimes refered to as Bologna Stone. Barite commonly occurs ...
Bauxite
Bauxite is a naturally occurring, heterogeneous material composed primarily of one or more aluminium hydroxide minerals, plus various mixtures of silica, iron oxide, titania, aluminosilicate, and other impurities in minor or trace amounts. The princ...
Beryl
The mineral beryl is a beryllium aluminium cyclosilicate with the chemical formula Be3Al2(SiO3)6. The hexagonal crystals of beryl may be very small or range to several meters in size. Terminated crystals are relatively rare. Beryl exhibits conchoidal f...
Beryllium
Beryllium is the chemical element in the periodic table that has the symbol Be and atomic number 4. A toxic bivalent element, beryllium is a steel grey, strong, light-weight yet brittle, alkaline earth metal, that is primarily used as a hardening agent...
Biotite
Biotite is a common phyllosilicate mineral that contains potassium, magnesium, iron and aluminium. It is sometimes called "iron mica" and is found in granitic rocks, gneisses, and schists. Like other mica minerals, biotite has a highly perfect basal cl...
Bornite
Bornite is a sulfide mineral with chemical composition Cu5FeS4 that crystallizes in the cubic system. It has a brown to copper-red color on fresh surfaces that tarnishes to an iridescent purple surface. Its purple to bronze iridescence gives it the nic...
Cadmium
Cadmium is a chemical element in the periodic table that has the symbol Cd and atomic number 48. A relatively rare, soft, bluish-white, toxic transition metal, cadmium occurs with zinc ores and is used largely in batteries. Notable characteristics ...
Calcite
he mineral calcite is a calcium carbonate corresponding to the formula CaCO3 and is one of the most widely distributed minerals on the Earth's surface. It is a common constituent of sedimentary rocks, limestone in particular. It is also the primary min...
Cassiterite
Cassiterite is a tin oxide mineral, SnO2. It is generally opaque, but is translucent in thin crystals. Its luster and multiple crystal faces produce a desirable gem. Cassiterite is the chief ore of tin today. Most sources of cassiterite today are fo...
Celestite
Celestite (SrSO4) is a mineral consisting of strontium sulfate. The mineral is also known as celestine and is named for its occasional delicate blue color. Celestite occurs as crystals, and also in compact massive and fibrous forms. It is mostly fou...
Chalcocite
Chalcocite, copper(I) sulfide (Cu2S), is an important copper mineral ore. It is opaque, being colored dark-gray to black with a metallic luster. It has a hardness of 2½ - 3. It is a sulfide with an orthorhombic crystal system. Chalcocite is somet...
Chalcopyrite
Chalcopyrite is a copper iron sulfide mineral that crystallizes in the tetragonal system. It has chemical composition CuFeS2. It has a brassy to golden yellow color and hardness of 3.5 to 4 on the Mohs scale. Due to its color it is often confused with ...
Chert
Chert is a fine-grained silica-rich cryptocrystalline sedimentary rock that may contain small fossils. It varies greatly in color from white to black, but most often manifests as gray, brown, grayish brown and light green to rusty red; its color is an ...
Chlorite
The term Chlorite can refer to the following meanings: - The chlorite group of clay minerals. - A Chlorite ion is a polyatomic anion consisting of an atom of chlorine and two oxygen atoms. Its chemical formula is ClO2-. The oxidation state of the...
Chromite (Iron Chromium Oxide)
Chromite, iron magnesium chromium oxide: (Fe,Mg)Cr2O4, is an oxide mineral belonging to the spinel group. Magnesium is always present in variable amounts, also aluminium and iron substitute for chromium. Chromite is found in peridotite and other lay...
Cinnabar
Cinnabar (German Zinnober), sometimes written cinnabarite, is a name applied to red mercury(II) sulfide (HgS), or native vermilion, the common ore of mercury. The name comes from the Greek, used by Theophrastus, and was probably applied to several dist...
Coal
Coal is a fossil fuel extracted from the ground either by underground mining, open-pit mining or strip mining. It is a readily combustible black or brownish-black sedimentary rock. It is composed primarily of carbon and hydrocarbons, along with assorte...
Cobalt
Cobalt is a chemical element in the periodic table that has the symbol Co and atomic number 27. Notable characteristics Cobalt is a hard ferromagnetic silver-white element. The Curie temperature is of 1388 K with 1.6~1.7 Bohr magnetons per atom. ...
Colemanite
Colemanite (Ca2B6O11·5H2O) is a borate mineral found in evaporite deposits. Colemanite is a secondary mineral that forms when borax is deposited, and then regularly covered with boron containing water. The boron remains after the water evaporates, a...
Conglomerate (geology)
In geology, a conglomerate is a rock consisting of other stones that have been cemented together. Conglomerates are sedimentary rocks consisting of subangular clasts and are thus differentiated from breccias, which consist of angular clasts. Both congl...
Copper
Copper is a chemical element in the periodic table that has the symbol Cu and atomic number 29. Notable characteristics Copper is a reddish-coloured metal, with a high electrical and thermal conductivity (among pure metals at room temperature, on...
Corundum
Corundum is the crystalline form of aluminium oxide and one of the rock-forming minerals. Corundum is naturally clear, but can have different colors when impurities are added. Transparent specimens are used as gems, called ruby if red, while all other ...
Creedite
Creedite is a calcium aluminium sulfate fluoro hydroxide mineral, Ca3Al2SO4(F,OH)10·2(H2O).
Cuprite
Cuprite is a mineral composed of copper(I) oxide Cu2O, and is an important ore of copper. Its dark crystals with red internal reflections are in the isometric system, appearing as cubic, octahedral, or dodecahedral forms, or in combinations, with a ...
Dioptase
Dioptase is an intense emerald-green to bluish-green copper cyclosilicate mineral. It is transparent to translucent. Its luster is vitreous to sub-adamantine. Its formula is CuSiO3·H2O (also reported as: CuSiO2(OH)2). It has a hardness of 5, the sam...
Diorite
Diorite is a grey to dark grey intermediate intrusive igneous rock composed principally of plagioclase feldspar (typically andesine), hornblende, and/or pyroxene. Varieties deficient in hornblende and other dark minerals are called leucodiorite. It is ...
Dolomite
Dolomite is a mineral (formula CaMg(CO3)2) consisting of a calcium magnesium carbonate found in crystals and in beds as dolostone. A pure form of dolostone would be rare, however; it usually intergrades with limestone and is referred to as dolomitic li...
Gabbro
Gabbro is a dark, coarse-grained, intrusive igneous rock chemically equivalent to basalt. It is a plutonic rock, formed when molten magma is trapped beneath the Earth's surface and cools slowly into a hard, coarsely crystalline mass. It is dense, green...
Galena
Galena is a lead ore. This article describes Galena's mineral properties. In its chemically purified form, Galena is known as Lead Sulfide; refer to that article for chemical and industrial uses. Galena is one of the most abundant and widely distrib...
Garnierite
Garnierite is a mineral composed of hydrous nickel silicates a member of the serpentine group with formula: (Ni,Mg)3Si2O5(OH). Népouite is a synonym. Garnierite is important as a source of nickel and is mined from laterite deposits which are form...
Garnet
The Garnet group of minerals show crystals with a habit of dodecahedrons and trapezohedrons. They are nesosilicates with the same general formula, A3B2(SiO4)3. The chemical elements in garnet include calcium, magnesium, aluminium, iron2+, iron3+, chrom...
Germanium
Germanium is a chemical element in the periodic table that has the symbol Ge and atomic number 32. This is a lustrous, hard, silver-white, metalloid that is chemically similar to tin. Germanium forms a large number of organometallic compounds and is an...
Gneiss
Gneiss is a common and widely distributed type of rock formed by high grade regional metamorphic processes from preexisting formations that were originally either igneous or sedimentary rocks. Gneissic rocks are coarsely laminated and largely recrystal...
Graphite
Graphite (named by Abraham Gottlob Werner in 1789, from the Greek γÏαφειν: "to draw/write", for its use in pencils) is one of the allotropes of carbon. Unlike diamond, graphite is a conductor, and can be used, for instance, as the...
Gypsum
Gypsum is a very soft mineral composed of calcium sulfate dihydrate, with the chemical formula CaSO4·2H2O. Chemical structure Heating gypsum above approximately 150°C (302°F) partially dehydrates the mineral by driving off exactly 75% of...
Hafnium
Hafnium is a chemical element in the periodic table that has the symbol Hf and atomic number 72. A lustrous, silvery gray tetravalent transition metal, hafnium resembles zirconium chemically and is found in zirconium minerals. Hafnium is used in tungst...
Hematite
Hematite (AE) or haematite (BE) is the mineral form of Iron (III) oxide, (Fe2O3), one of several iron oxides. The ore sometimes contains slight amounts of titanium. When shaped into ornaments, it is often called black diamond. Hematite is a very com...
Salt (Halite)
Halite is the mineral of sodium chloride, NaCl, commonly known as rock salt. Halite forms isometric crystals. The mineral is colorless to white, light blue, dark blue, and pink. It commonly occurs with other evaporite deposit minerals such as several o...
Indium
Indium is a chemical element in the periodic table that has the symbol In and atomic number 49. This rare, soft, malleable and easily fusible poor metal, is chemically similar to aluminium or gallium but looks more like zinc (zinc ores are also the pri...
Iron oxide
There are a number of iron oxides: Iron oxides Iron(II) oxide or ferrous oxide (FeO) The black-coloured powder in particular can cause explosions as it readily ignites. Iron(III) oxide or ferric oxide (Fe2O3) known in its natural state as hema...
Kaolinite
Kaolinite is a mineral with the chemical composition Al2Si2O5(OH)4. It is a layered silicate mineral, with one tetrahedral sheet linked through oxygen molecules to one octahedral sheet of alumina octahedra. It is also known as china clay and kaolin (é...
Kyanite
The mineral kyanite is an aluminium silicate of the sillimanite group (along with andalusite and sillimanite), also called alumino-silicate. It has the formula Al2O3·SiO2 (Al2SiO5). Its hardness varies widely depending on its crystallographic direct...
Lead
Lead is a chemical element in the periodic table that has the symbol Pb (L. Plumbum) and atomic number 82. A soft, heavy, toxic and malleable poor metal, lead is bluish white when freshly cut but tarnishes to dull gray when exposed to air. Lead is used...
Limestone
Limestone is a sedimentary rock composed of the mineral calcite (calcium carbonate). The primary source of this calcite is usually marine organisms. These organisms secrete shells that settle out of the water column and are deposited on ocean floors as...
Limonite
Limonite Limonite is a ferric hydrate of varying composition, the generic formula is frequently written as FeO(OH)·nH2O, although this is not entirely accurate as Limonite often contains a varying amount of oxide compared to hydroxide. Together w...
Lithium
Lithium is the chemical element with symbol Li and atomic number 3. In the periodic table, it is located in group 1, among the alkali metals. Lithium in its pure form is a soft, silver white metal, that tarnishes and oxidizes very rapidly in air and wa...
Magnesium
Magnesium is the chemical element in the periodic table that has the symbol Mg and atomic number 12. Magnesium is the eighth most abundant element and constitutes about 2% of the Earth's crust, and it is the third most plentiful element dissolved in se...
Magnetite
Magnetite is a magnetic mineral form of both iron(II) oxide and iron(III) oxide or (iron(II,III) oxide), with chemical formula Fe3O4, one of several iron oxides and a member of the spinel group. Magnetite is the most magnetic of all the minerals on ...
Malachite
Malachite is a carbonate mineral, copper(II) carbonate hydroxide Cu2CO3(OH)2. Malachite has a hardness between 3.5 and 4. It crystallizes in the monoclinic crystal system, and most often forms botryoidal, fibrous, or stalagtitic masses. Malachite of...
Manganite (Manganese oxide)
Manganese is a chemical element in the periodic table that has the symbol Mn and atomic number 25. Notable characteristics Manganese is a gray-white metal, resembling iron. It is a hard metal and is very brittle, fusible with difficulty, but easi...
Marble
Marble is metamorphosed limestone, composed of fairly pure calcite (a crystalline form of calcium carbonate, CaCO3). It is extensively used for sculpture, as a building material, and in many other applications. Faux marble or faux marbling is a wall...
Ore of Mercury
Mercury (element) Mercury, also called quicksilver, is a chemical element in the periodic table that has the symbol Hg (from the Greek hydrargyrum, for watery (or liquid) silver) and atomic number 80. A heavy, silvery, transition metal, mercury is o...
Mica
The mica group of minerals includes several closely related materials having highly perfect basal cleavage. All are monoclinic with a tendency towards pseudo-hexagonal crystals and are similar in chemical composition. The highly perfect cleavage, which...
Molybdenite
Molybdenite is a mineral of molybdenum disulfide, MoS2. Similar in appearance and feel to graphite, molybdenite has a lubricating effect which is produced by its structure of close-spaced parallel cleavage planes. Finely powdered MoS2, with particle si...
Monazite
In geology, the mineral monazite is a reddish-brown phosphate containing rare earth metals and an important source of thorium, lanthanum, and cerium. It occurs usually in small isolated crystals. There are actually three different kinds of monazite, de...
Murdochite
Murdochite is a mineral combining lead and copper oxides. It was first discovered in 1953 in Arizona.
Muscovite
Muscovite, also known as potash mica, is a phyllosilicate mineral of aluminium and potassium. It has a highly perfect basal cleavage yielding remarkably thin laminae (sheets), which are often highly elastic. Muscovite has a hardness of 2 - 2.25 and a s...
Orpiment
Orpiment is a common monoclinic crystalline mineral - Chemical Composition: As2S3, arsenic trisulfide - Molecular Weight: 246.04 gm - Hardness: 1.5-2 - Optical refractive index: Biaxial (-), a=2.4, b=2.81, g=3.02 Orpiment is a mineral th...
Pentlandite
Pentlandite is a iron-nickel sulfide, (Fe,Ni)9S8. Pentlandite usually has a Ni:Fe ratio of close to 1:1. It also contains minor cobalt. Pentlandite forms isometric crystals, but is normally found in massive granular aggregates. It is brittle with a ...
Peridotite
Peridotite is a dense, coarse grained ultrabasic rock, consisting mainly of the minerals olivine and pyroxene. Peridotite is also a group of mantle derived igneous rocks. They all are ultramafic or ultrabasic meaning they contain less than 45% silica a...
Perlite
Perlite is an amorphous glass mineral of volcanic origin. Typical analysis: 70-75% SiO2, 12-15% Al2O3, Na2O 3-4%, K2O 3-5%, Fe2O3 0,5-2%, MgO 0,2-0,7%, CaO 0,5-1,5% Loss On Ignition 3-5% Properties: When it reaches temperatures of 850"“900 °...
Phosphate
In chemistry, a phosphate is a polyatomic ion or radical consisting of one phosphorus atom and four oxygen. In the ionic form, it carries a -3 formal charge, and is denoted PO43-. In a biochemical setting, a free phosphate ion in solution is called ...
Phyllite
Phyllite is a type of metamorphic rock primarily composed of quartz, sericite mica, and chlorite; the rock is intermediate in grade between slate and mica schist. Minute crystals of graphite, sericite, or chlorite impart a silky sheen to the surfaces o...
Pyrolusite
Pyrolusite is a mineral consisting essentially of manganese dioxide (Mn02) and is important as an ore of manganese. It is a soft, black, amorphous mineral, often with a granular, fibrous or columnar structure, sometimes forming reniform crusts. It has ...
Quartz
Quartz is the second most abundant mineral in the Earth's crust. It has a hexagonal crystal structure made of trigonal crystallized silica (silicon dioxide, SiO2), with a hardness of 7 on the Mohs scale. Density is 2.6 g/cm³. The typical shape is a ...
Quartzite
Quartzite is a hard, metamorphic rock which was originally sandstone. Through heating and pressure usually related to tectonic compression within orogenic belts, the original quartz sand grains and quartz silica cement were fused into one. Pure quartzi...
Platinum
Platinum is a chemical element in the periodic table that has the symbol Pt and atomic number 78. A heavy, malleable, ductile, precious, gray-white transition metal, platinum is resistant to corrosion and occurs in some nickel and copper ores along wit...
Potash
Potash (or carbonate of potash) is an impure form of potassium carbonate (K2CO3) mixed with other potassium salts. Potash has been used since antiquity in the manufacture of glass and soap, and as a fertilizer. The name comes from the English words pot...
Rare Earth Ore
A rare earth is an oxide of a rare earth element. Often rare earth elements themselves are loosely called "rare earths". As to exactly what is a "rare earth" element is a matter of some ambiguity. The narrowest definition restricts it to the lanthanide...
Realgar
Realgar is a mineral of arsenic sulfide, AsS. Realgar, orpiment, and arsenopyrite provide nearly all the world's supply of arsenic as a byproduct of smelting concentrates derived from these ores.
Rhyolite
Rhyolite is an igneous, volcanic (extrusive) rock, of felsic composition, with aphanitic to porphyritic texture. Mineral assembly is usually quartz, alkali feldspar and plagioclase (in a ratio > 1:2). Biotite and pyroxene are common accessory minerals....
Salt
In chemistry, salt is a general term used for ionic compounds composed of positively charged cations and negatively charged anions, so that the product is neutral and without a net charge. These ions can be inorganic (Cl-) as well as organic (CH3-COO-)...
Sandstone
Sandstone is an arenaceous sedimentary rock composed mainly of feldspar and quartz and varies in colour (in a similar way to sand), through grey, yellow, red, and white. Since sandstones often form highly visible cliffs and other rock formations, certa...
Scheelite
Scheelite is a calcium tungstate mineral with the chemical formula CaWO4. It is an important ore of tungsten. Well-formed crystals are sought by collectors and are occasionally fastened into gemstones when suitably free of flaws. Scheelite has been syn...
Schist
The schists form a group of medium-grade metamorphic rocks, chiefly notable for the preponderance of lamellar minerals such as micas, chlorite, talc, hornblende, graphite, and others. Quartz often occurs in drawn-out grains to such an extent that a par...
Scoria
Scoria is a term used by geologists to describe an igneous rock containing many gas bubbles, or vesicules. Scoria forms when magma rich in dissolved gases is vented. As the magma encounters lower pressures, the gasses are able to escape and form bub...
Selenite
Selenite (chemical formula: CaSO4·2H2O) is a hydrous calcium sulfate, meaning it is composed of oxygen, sulfur, hydrogen, calcium and water. It is basically a glassy, well-crystallized form of gypsum and is often referred to as satin spar. Seleni...
Serpentine
Serpentine is a group of common rock-forming hydrous magnesium iron phyllosilicate ((Mg,Fe)3Si2O5(OH)4) minerals. In mineralogy, serpentine may refer to any of 20 minerals belonging to the serpentine group. Owing to admixture, these minerals are not al...
Shale
Shale is a fine-grained sedimentary rock whose original constituents were clays or muds. It is characterized by thin laminae breaking with an irregular curving fracture, often splintery, and parallel to the often indistinguishable bedding planes. Non-f...
Siderite
Siderite is a mineral composed of iron carbonate FeCO3. It is a valuable iron mineral, since it is 48% iron and contains no sulfur or phosphorus. Both magnesium and manganese commonly substitute for the iron. Its crystals belong to the hexagonal sys...
Sillimanite
Sillimanite is an alumino-sillicate mineral with the chemical formula Al2SiO5. Sillimanite is named after the American chemist B. Silliman (1779-1824). Occurrence Sillimanite is one of three alumino-sillicate polymorphs, the other two being andal...
Siltstone
Siltstone is a sedimentary rock that is intermediate in grain size between the coarser sandstone and the finer shale. As its name implies, it is primarily composed of silt, defined as grains smaller than 62 micrometres. Siltstones were at one time ofte...
Silver
Silver is a chemical element in the periodic table that has the symbol Ag (from the traditional abbreviation from the Latin Argentum) and atomic number 47. A soft white lustrous transition metal, silver has the highest electrical and thermal conductivi...
Slate
Slate is a fine-grained, homogeneous, sedimentary rock composed of clay or volcanic ash which has been metamorphosed (foliated) in layers (bedded deposits). Slate can be made into roofing shingles ('roofing slates' in the United Kingdom), because it ha...
Smithsonite
Smithsonite, or zinc spar, is zinc carbonate ZnCO3, a mineral ore of zinc. Historically, smithsonite was identified with hemimorphite before it was realised that they were two distinct minerals. The two minerals are very similar in appearance and the t...
Sphalerite
Sphalerite (ZnS) is a mineral that is the chief ore of zinc. It consists largely of zinc sulfide in crystalline form but almost always contains variable iron as (Zn,Fe)S. It is usually found in association with galena, pyrite, and other sulfides along ...
Stibnite
Stibnite, sometimes also called antimonite, is a sulfide mineral. It crystallizes in the orthorhombic system, has hardness 2 and a grey colour. Its chemical composition is described by the formula Sb2S3 Stibnite is the most important source for the ...
Sulfur
Sulfur (or Sulphur; see spelling below) is the chemical element in the periodic table that has the symbol S and atomic number 16. It is an abundant, tasteless, odorless, multivalent non-metal. Sulfur, in its native form, is a yellow crystaline solid. I...
Syenite
Syenite is a coarse-grained intrusive igneous rock of the same general composition as granite but with the quartz either absent or present in relatively small amounts. The feldspars are alkaline in character and the dark mineral is usually hornblende. ...
Talc
Talc is a mineral composed of hydrated magnesium silicate with the chemical formula H2Mg3(SiO3)4 or Mg3Si4O10(OH)2. It occurs as foliated to fibrous masses, its monoclinic crystals being so rare as to be almost unknown. It has a perfect basal cleavage,...
Tennantite
Tennantite is a copper arsenic sulfide mineral. Its chemical formula is Cu12As4S13. It is found in hydrothermal veins and contact metamorphic deposits. A closely related mineral, tetrahedrite (Cu12Sb4S13) has antimony substituting for arsenic and the t...
Tin
Tin is a chemical element in the periodic table that has the symbol Sn (L. Stannum) and atomic number 50. This silvery, malleable poor metal that is not easily oxidized in air and resists corrosion is found in many alloys and is used to coat other meta...
Tincalconite
Tincalconite is a mineral closely related to borax, and is a secondary mineral that forms if borax is allowed to dry. The crystal shape of borax does not change during the drying process. Its formula is Na2B4O5(OH)4 - 3H2O or Na2B4O7 - 5H2O. While m...
Titanium
Titanium is a chemical element in the periodic table that has the symbol Ti and atomic number 22. It is a light, strong, lustrous, corrosion-resistant (including resistance to sea water and chlorine) transition metal with a white-silvery-metallic color...
Topaz
The mineral topaz is a silicate of aluminium and fluorine with the chemical formula (AlF)2SiO4. It is orthorhombic and its crystals are mostly prismatic terminated by pyramidal and other faces, the basal pinacoid often being present. It has an easy and...
Tourmaline
The mineral tourmaline is chemically one of the most complicated silicate minerals. It is a complex silicate of aluminium and boron but because of isomorphous replacement (solid solution) its composition varies widely with iron, magnesium and lithium a...
Travertine
Travertine is a white concretionary form of calcium carbonate that is usually hard and semicrystalline. It is deposited from the water of mineral springs (especially hot springs) or streams holding lime in solution. Extensive deposits exist at Tivoli, ...
Tungsten
Tungsten (formerly Wolfram) is a chemical element in the periodic table that has the symbol W (L. Wolframium) and atomic number 74. A very hard, heavy, steel-gray to white transition metal, tungsten is found in several ores including wolframite and sch...
Uranium
Uranium is a chemical element in the periodic table that has the symbol U and atomic number 92. A heavy, silvery-white, toxic, metallic, and naturally-radioactive element, uranium belongs to the actinide series and its isotope 235U is used as the fuel ...
Vanadinite
Vanadinite is a mineral with the formula Pb5(VO4)3Cl, lead chlorovanadate. It is part of a series with two other minerals: pyromorphite (Pb5(PO4)3Cl) and mimetite (Pb5(AsO4)3Cl). It has hexagonal crystals, usually prismatic but the crystals are ofte...
Vermiculite
Vermiculite is a natural mineral which expands with the application of heat. It is formed by hydration of certain basaltic minerals, and is often found in association with asbestos. Mining operations in Libby, Montana were closed in 1990 in response to...
Volcanic ash
Volcanic ash is the term for very fine rock and mineral particles less than 2 mm in diameter that are ejected from a volcanic vent. Ash is created when solid rock shatters and magma separates into minute particles during explosive volcanic activity. Th...
Wollastonite
Wollastonite is a calcium inosilicate mineral (CaSiO3) that may contain small amounts of iron, magnesium, and manganese substituting for calcium. It is usually white. It forms when impure limestone or dolostone is subjected to high temperature and pres...
Wulfenite
Wulfenite is a lead molybdate mineral with the formula PbMoO4. It can be most often found as thin tabular crystals with a bright orange-red to yellow-orange color, sometimes brown, although the color can be highly variable. Wulfenite is found in ...
Zeolite
Zeolites (Greek, zein,"to boil";lithos,"a stone") are minerals that have a porous structure. There are about four dozen recognized naturally occurring zeolite minerals and as many or more synthetic varieties. They are basically hydrated alumino-silicat...
Zinc
Zinc is a chemical element in the periodic table that has the symbol Zn and atomic number 30. Notable characteristics Zinc is a moderately reactive metal that will combine with oxygen and other non-metals, and will react with dilute acids to rele...
Zircon Dust
Zircon is a mineral belonging to the group of nesosilicates. Its chemical formula is ZrSiO4. Hafnium is almost always present ranging from 1 to 4%. The crystal structure of zircon is tetragonal crystal class. The natural color of zircon varies between ...