Portal:Minerals

The Minerals Portal

In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid substance with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.

The geological definition of mineral normally excludes compounds that occur only in living organisms. However, some minerals are often biogenic (such as calcite) or organic compounds in the sense of chemistry (such as mellite). Moreover, living organisms often synthesize inorganic minerals (such as hydroxylapatite) that also occur in rocks.

The concept of mineral is distinct from rock, which is any bulk solid geologic material that is relatively homogeneous at a large enough scale. A rock may consist of one type of mineral or may be an aggregate of two or more different types of minerals, spacially segregated into distinct phases.

Some natural solid substances without a definite crystalline structure, such as opal or obsidian, are more properly called mineraloids. If a chemical compound occurs naturally with different crystal structures, each structure is considered a different mineral species. Thus, for example, quartz and stishovite are two different minerals consisting of the same compound, silicon dioxide. (Full article...)

Mineralogy is a subject of geology specializing in the scientific study of the chemistry, crystal structure, and physical (including optical) properties of minerals and mineralized artifacts. Specific studies within mineralogy include the processes of mineral origin and formation, classification of minerals, their geographical distribution, and their utilization. (Full article...)

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Image 1

The 423-carat (85 g) blue Logan Sapphire

Sapphire is a precious gemstone, a variety of the mineral corundum, consisting of aluminium oxide (α-Al₂O₃) with trace amounts of elements such as iron, titanium, cobalt, lead, chromium, vanadium, magnesium, boron, and silicon. The name sapphire is derived from the Latin word sapphirus, itself from the Greek word sappheiros (σάπφειρος), which referred to lapis lazuli. It is typically blue, but natural "fancy" sapphires also occur in yellow, purple, orange, and green colors; "parti sapphires" show two or more colors. Red corundum stones also occur, but are called rubies rather than sapphires. Pink-colored corundum may be classified either as ruby or sapphire depending on the locale. Commonly, natural sapphires are cut and polished into gemstones and worn in jewelry. They also may be created synthetically in laboratories for industrial or decorative purposes in large crystal boules. Because of the remarkable hardness of sapphires – 9 on the Mohs scale (the third-hardest mineral, after diamond at 10 and moissanite at 9.5) – sapphires are also used in some non-ornamental applications, such as infrared optical components, high-durability windows, wristwatch crystals and movement bearings, and very thin electronic wafers, which are used as the insulating substrates of special-purpose solid-state electronics such as integrated circuits and GaN-based blue LEDs. It occurs in association with ruby, zircon, biotite, muscovite, calcite, dravite and quartz. (Full article...)
$Image 2 Graphite specimen Graphite (/ˈɡræfaɪt/) is a crystalline allotrope (form) of the element carbon. It consists of many stacked layers of graphene, typically in excess of hundreds of layers. Graphite occurs naturally and is the most stable form of carbon under standard conditions. Synthetic and natural graphite are consumed on a large scale (1.3 million metric tons per year in 2022) for uses in many critical industries including refractories (50%), lithium-ion batteries (18%), foundries (10%), and lubricants (5%), among others (17%). Graphite converts to diamond under extremely high pressure and temperature. Graphite's low cost, thermal and chemical inertness and characteristic conductivity of heat and electricity finds numerous applications in high energy and high temperature processes. (Full article...)$

Image 2

Graphite specimen

Graphite (/ˈɡræfaɪt/) is a crystalline allotrope (form) of the element carbon. It consists of many stacked layers of graphene, typically in excess of hundreds of layers. Graphite occurs naturally and is the most stable form of carbon under standard conditions. Synthetic and natural graphite are consumed on a large scale (1.3 million metric tons per year in 2022) for uses in many critical industries including refractories (50%), lithium-ion batteries (18%), foundries (10%), and lubricants (5%), among others (17%). Graphite converts to diamond under extremely high pressure and temperature. Graphite's low cost, thermal and chemical inertness and characteristic conductivity of heat and electricity finds numerous applications in high energy and high temperature processes. (Full article...)
$Image 3 Deep green isolated fluorite crystal resembling a truncated octahedron, set upon a micaceous matrix, from Erongo Mountain, Erongo Region, Namibia (overall size: 50 mm × 27 mm, crystal size: 19 mm wide, 30 g) Fluorite (also called fluorspar) is the mineral form of calcium fluoride, CaF2. It belongs to the halide minerals. It crystallizes in isometric cubic habit, although octahedral and more complex isometric forms are not uncommon. The Mohs scale of mineral hardness, based on scratch hardness comparison, defines value 4 as fluorite. Pure fluorite is colourless and transparent, both in visible and ultraviolet light, but impurities usually make it a colorful mineral and the stone has ornamental and lapidary uses. Industrially, fluorite is used as a flux for smelting, and in the production of certain glasses and enamels. The purest grades of fluorite are a source of fluoride for hydrofluoric acid manufacture, which is the intermediate source of most fluorine-containing fine chemicals. Optically clear transparent fluorite has anomalous partial dispersion, that is, its refractive index varies with the wavelength of light in a manner that differs from that of commonly used glasses, so fluorite is useful in making apochromatic lenses, and particularly valuable in photographic optics. Fluorite optics are also usable in the far-ultraviolet and mid-infrared ranges, where conventional glasses are too opaque for use. Fluorite also has low dispersion, and a high refractive index for its density. (Full article...)$

Image 3

Deep green isolated fluorite crystal resembling a truncated octahedron, set upon a micaceous matrix, from Erongo Mountain, Erongo Region, Namibia (overall size: 50 mm × 27 mm, crystal size: 19 mm wide, 30 g)

Fluorite (also called fluorspar) is the mineral form of calcium fluoride, CaF₂. It belongs to the halide minerals. It crystallizes in isometric cubic habit, although octahedral and more complex isometric forms are not uncommon.

The Mohs scale of mineral hardness, based on scratch hardness comparison, defines value 4 as fluorite.

Pure fluorite is colourless and transparent, both in visible and ultraviolet light, but impurities usually make it a colorful mineral and the stone has ornamental and lapidary uses. Industrially, fluorite is used as a flux for smelting, and in the production of certain glasses and enamels. The purest grades of fluorite are a source of fluoride for hydrofluoric acid manufacture, which is the intermediate source of most fluorine-containing fine chemicals. Optically clear transparent fluorite has anomalous partial dispersion, that is, its refractive index varies with the wavelength of light in a manner that differs from that of commonly used glasses, so fluorite is useful in making apochromatic lenses, and particularly valuable in photographic optics. Fluorite optics are also usable in the far-ultraviolet and mid-infrared ranges, where conventional glasses are too opaque for use. Fluorite also has low dispersion, and a high refractive index for its density. (Full article...)
Image 4

Tourmaline (/ˈtʊərməlɪn, -ˌliːn/ TOOR-mə-lin, -⁠leen) is a crystalline silicate mineral group in which boron is compounded with elements such as aluminium, iron, magnesium, sodium, lithium, or potassium. This gemstone comes in a wide variety of colors.

The name is derived from the Sinhalese tōramalli (ටෝරමල්ලි), which refers to the carnelian gemstones. (Full article...)
Image 5
Crystal structure of table salt (sodium in purple, chlorine in green)

In crystallography, crystal structure is a description of the ordered arrangement of atoms, ions, or molecules in a crystalline material. Ordered structures occur from the intrinsic nature of constituent particles to form symmetric patterns that repeat along the principal directions of three-dimensional space in matter.

The smallest group of particles in a material that constitutes this repeating pattern is the unit cell of the structure. The unit cell completely reflects the symmetry and structure of the entire crystal, which is built up by repetitive translation of the unit cell along its principal axes. The translation vectors define the nodes of the Bravais lattice.

The lengths of principal axes/edges, of the unit cell and angles between them are lattice constants, also called lattice parameters or cell parameters. The symmetry properties of a crystal are described by the concept of space groups. All possible symmetric arrangements of particles in three-dimensional space may be described by 230 space groups.

The crystal structure and symmetry play a critical role in determining many physical properties, such as cleavage, electronic band structure, and optical transparency. (Full article...)
Image 6

Hematite crystals from Brazil

Hematite (/ˈhiːməˌtaɪt, ˈhɛmə-/), also spelled as haematite, is a common iron oxide compound with the formula, Fe₂O₃ and is widely found in rocks and soils. Hematite crystals belong to the rhombohedral lattice system which is designated the alpha polymorph of Fe
₂O
₃. It has the same crystal structure as corundum (Al
₂O
₃) and ilmenite (FeTiO
₃). With this crystal structure geometry it forms a complete solid solution at temperatures above 950 °C (1,740 °F).

Hematite occurs naturally in black to steel or silver-gray, brown to reddish-brown, or red colors. It is mined as an important ore mineral of iron. It is electrically conductive. Hematite varieties include kidney ore, martite (pseudomorphs after magnetite), iron rose and specularite (specular hematite). While these forms vary, they all have a rust-red streak. Hematite is not only harder than pure iron, but also much more brittle. The term kidney ore may be broadly used to describe botryoidal, mammillary, or reniform hematite. Maghemite is a polymorph of hematite (γ-Fe
₂O
₃) with the same chemical formula, but with a spinel structure like magnetite.

Large deposits of hematite are found in banded iron formations. Gray hematite is typically found in places that have still, standing water, or mineral hot springs, such as those in Yellowstone National Park in North America. The mineral may precipitate in the water and collect in layers at the bottom of the lake, spring, or other standing water. Hematite can also occur in the absence of water, usually as the result of volcanic activity.

Clay-sized hematite crystals also may occur as a secondary mineral formed by weathering processes in soil, and along with other iron oxides or oxyhydroxides such as goethite, which is responsible for the red color of many tropical, ancient, or otherwise highly weathered soils. (Full article...)
$Image 7 A rich seam of iridescent opal encased in matrix Opal is a hydrated amorphous form of silica (SiO2·nH2O); its water content may range from 3% to 21% by weight, but is usually between 6% and 10%. Due to the amorphous (chemical) physical structure, it is classified as a mineraloid, unlike crystalline forms of silica, which are considered minerals. It is deposited at a relatively low temperature and may occur in the fissures of almost any kind of rock, being most commonly found with limonite, sandstone, rhyolite, marl, and basalt. The name opal is believed to be derived from the Sanskrit word upala (उपल), which means 'jewel', and later the Greek derivative opállios (ὀπάλλιος). There are two broad classes of opal: precious and common. Precious opal displays play-of-color (iridescence); common opal does not. Play-of-color is defined as "a pseudo chromatic optical effect resulting in flashes of colored light from certain minerals, as they are turned in white light." The internal structure of precious opal causes it to diffract light, resulting in play-of-color. Depending on the conditions in which it formed, opal may be transparent, translucent, or opaque, and the background color may be white, black, or nearly any color of the visual spectrum. Black opal is considered the rarest, while white, gray, and green opals are the most common. (Full article...)$

Image 7

A rich seam of iridescent opal encased in matrix

Opal is a hydrated amorphous form of silica (SiO₂·nH₂O); its water content may range from 3% to 21% by weight, but is usually between 6% and 10%. Due to the amorphous (chemical) physical structure, it is classified as a mineraloid, unlike crystalline forms of silica, which are considered minerals. It is deposited at a relatively low temperature and may occur in the fissures of almost any kind of rock, being most commonly found with limonite, sandstone, rhyolite, marl, and basalt.

The name opal is believed to be derived from the Sanskrit word upala (उपल), which means 'jewel', and later the Greek derivative opállios (ὀπάλλιος).

There are two broad classes of opal: precious and common. Precious opal displays play-of-color (iridescence); common opal does not. Play-of-color is defined as "a pseudo chromatic optical effect resulting in flashes of colored light from certain minerals, as they are turned in white light." The internal structure of precious opal causes it to diffract light, resulting in play-of-color. Depending on the conditions in which it formed, opal may be transparent, translucent, or opaque, and the background color may be white, black, or nearly any color of the visual spectrum. Black opal is considered the rarest, while white, gray, and green opals are the most common. (Full article...)
$Image 8 A crystalline solid: atomic resolution image of strontium titanate. Brighter spots are columns of strontium atoms and darker ones are titanium-oxygen columns. Crystallography is the branch of science devoted to the study of molecular and crystalline structure and properties. The word crystallography is derived from the Ancient Greek word κρύσταλλος (krústallos; "clear ice, rock-crystal"), and γράφειν (gráphein; "to write"). In July 2012, the United Nations recognised the importance of the science of crystallography by proclaiming 2014 the International Year of Crystallography. Crystallography is a broad topic, and many of its subareas, such as X-ray crystallography, are themselves important scientific topics. Crystallography ranges from the fundamentals of crystal structure to the mathematics of crystal geometry, including those that are not periodic or quasicrystals. At the atomic scale it can involve the use of X-ray diffraction to produce experimental data that the tools of X-ray crystallography can convert into detailed positions of atoms, and sometimes electron density. At larger scales it includes experimental tools such as orientational imaging to examine the relative orientations at the grain boundary in materials. Crystallography plays a key role in many areas of biology, chemistry, and physics, as well as in emerging developments in these fields. (Full article...)$

Image 8
A crystalline solid: atomic resolution image of strontium titanate. Brighter spots are columns of strontium atoms and darker ones are titanium-oxygen columns.

Crystallography is the branch of science devoted to the study of molecular and crystalline structure and properties. The word crystallography is derived from the Ancient Greek word κρύσταλλος (krústallos; "clear ice, rock-crystal"), and γράφειν (gráphein; "to write"). In July 2012, the United Nations recognised the importance of the science of crystallography by proclaiming 2014 the International Year of Crystallography.

Crystallography is a broad topic, and many of its subareas, such as X-ray crystallography, are themselves important scientific topics. Crystallography ranges from the fundamentals of crystal structure to the mathematics of crystal geometry, including those that are not periodic or quasicrystals. At the atomic scale it can involve the use of X-ray diffraction to produce experimental data that the tools of X-ray crystallography can convert into detailed positions of atoms, and sometimes electron density. At larger scales it includes experimental tools such as orientational imaging to examine the relative orientations at the grain boundary in materials. Crystallography plays a key role in many areas of biology, chemistry, and physics, as well as in emerging developments in these fields. (Full article...)
Image 9

Kaolinite (/ˈkeɪ.ələˌnaɪt, -lɪ-/ KAY-ə-lə-nyte, -⁠lih-; also called kaolin) is a clay mineral, with the chemical composition Al₂Si₂O₅(OH)₄. It is a layered silicate mineral, with one "tetrahedral" sheet of silicate tetrahedrons (SiO₄) linked to one "octahedral" sheet of aluminate octahedrons (AlO₂(OH)₄) through oxygen atoms on one side, and another such sheet through hydrogen bonds on the other side.

Kaolinite is a soft, earthy, usually white, mineral (dioctahedral phyllosilicate clay), produced by the chemical weathering of aluminium silicate minerals like feldspar. It has a low shrink–swell capacity and a low cation-exchange capacity (1–15 meq/100 g).

Rocks that are rich in kaolinite, and halloysite, are known as kaolin (/ˈkeɪ.əlɪn/) or china clay. In many parts of the world kaolin is colored pink-orange-red by iron oxide, giving it a distinct rust hue. Lower concentrations of iron oxide yield the white, yellow, or light orange colors of kaolin. Alternating lighter and darker layers are sometimes found, as at Providence Canyon State Park in Georgia, United States.

Kaolin is an important raw material in many industries and applications. Commercial grades of kaolin are supplied and transported as powder, lumps, semi-dried noodle or slurry. Global production of kaolin in 2021 was estimated to be 45 million tonnes, with a total market value of US $4.24 billion. (Full article...)
Image 10

Garnets ( /ˈɡɑːrnɪt/) are a group of silicate minerals that have been used since the Bronze Age as gemstones and abrasives.

Garnet minerals, while sharing similar physical and crystallographic properties, exhibit a wide range of chemical compositions, defining distinct species. These species fall into two primary solid solution series: the pyralspite series (pyrope, almandine, spessartine), with the general formula [Mg,Fe,Mn]₃Al₂(SiO₄)₃; and the ugrandite series (uvarovite, grossular, andradite), with the general formula Ca₃[Cr,Al,Fe]₂(SiO₄)₃. Notable varieties of grossular include hessonite and tsavorite.

Although garnets are often associated with metamorphism, it can also occuur in volcanic rocks on rare occasions. (Full article...)
$Image 11 Quartz crystal cluster from Brazil Quartz is a hard mineral composed of silica (silicon dioxide). The atoms are linked in a continuous framework of SiO4 silicon–oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical formula of SiO2. Quartz is, therefore, classified structurally as a framework silicate mineral and compositionally as an oxide mineral. Quartz is the second most abundant of the minerals and mineral groups that compose the Earth's lithosphere, with the feldspars making up 41% of the lithosphere by weight, followed by quartz making up 12%, and the pyroxenes at 11%. Quartz exists in two forms, the normal α-quartz and the high-temperature β-quartz, both of which are chiral. The transformation from α-quartz to β-quartz takes place abruptly at 573 °C (846 K; 1,063 °F). Since the transformation is accompanied by a significant change in volume, it can easily induce microfracturing of ceramics or rocks passing through this temperature threshold. There are many different varieties of quartz, several of which are classified as gemstones. Since antiquity, varieties of quartz have been the most commonly used minerals in the making of jewelry and hardstone carvings, especially in Europe and Asia. Quartz is the mineral defining the value of 7 on the Mohs scale of hardness, a qualitative scratch method for determining the hardness of a material to abrasion. (Full article...)$

Image 11

Quartz crystal cluster from Brazil

Quartz is a hard mineral composed of silica (silicon dioxide). The atoms are linked in a continuous framework of SiO₄ silicon–oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical formula of SiO₂. Quartz is, therefore, classified structurally as a framework silicate mineral and compositionally as an oxide mineral. Quartz is the second most abundant of the minerals and mineral groups that compose the Earth's lithosphere, with the feldspars making up 41% of the lithosphere by weight, followed by quartz making up 12%, and the pyroxenes at 11%.

Quartz exists in two forms, the normal α-quartz and the high-temperature β-quartz, both of which are chiral. The transformation from α-quartz to β-quartz takes place abruptly at 573 °C (846 K; 1,063 °F). Since the transformation is accompanied by a significant change in volume, it can easily induce microfracturing of ceramics or rocks passing through this temperature threshold.

There are many different varieties of quartz, several of which are classified as gemstones. Since antiquity, varieties of quartz have been the most commonly used minerals in the making of jewelry and hardstone carvings, especially in Europe and Asia.

Quartz is the mineral defining the value of 7 on the Mohs scale of hardness, a qualitative scratch method for determining the hardness of a material to abrasion. (Full article...)
Image 12
Frameworks of LTA-type (left) and FAU-type zeolites (right)

Zeolites are a group of several microporous, crystalline aluminosilicate minerals commonly used as commercial adsorbents and catalysts. They mainly consist of silicon, aluminium, and oxygen, and have the general formula Mⁿ⁺
_1/n(AlO
₂)⁻
(SiO
₂)
_x･yH
₂O where Mⁿ⁺
_1/n is either a metal ion or H⁺.

The term was originally coined in 1756 by Swedish mineralogist Axel Fredrik Cronstedt, who observed that rapidly heating a material, believed to have been stilbite, produced large amounts of steam from water that had been adsorbed by the material. Based on this, he called the material zeolite, from the Greek ζέω (zéō), meaning "to boil" and λίθος (líthos), meaning "stone".

Zeolites occur naturally, but are also produced industrially on a large scale. As of December 2018^[update], 253 unique zeolite frameworks have been identified, and over 40 naturally occurring zeolite frameworks are known. Every new zeolite structure that is obtained is examined by the International Zeolite Association Structure Commission (IZA-SC) and receives a three-letter designation. (Full article...)
Image 13

Beachy Head is a part of the extensive Southern England Chalk Formation.

Chalk is a soft, white, porous, sedimentary carbonate rock. It is a form of limestone composed of the mineral calcite and originally formed under the sea by the accumulation and lithification of hard parts of organisms, mostly microscopic plankton, which had settled to the sea floor. Chalk is common throughout Western Europe, where deposits underlie parts of France, and steep cliffs are often seen where they meet the sea in places such as the Dover cliffs on the Kent coast of the English Channel.

Chalk is mined for use in industry, such as for quicklime, bricks and builder's putty, and in agriculture, for raising pH in soils with high acidity. It is also used for "blackboard chalk" for writing and drawing on various types of surfaces, although these can also be manufactured from other carbonate-based minerals, or gypsum. (Full article...)
$Image 14 Rutile is an oxide mineral composed of titanium dioxide (TiO2), the most common natural form of TiO2. Rarer polymorphs of TiO2 are known, including anatase, akaogiite, and brookite. Rutile has one of the highest refractive indices at visible wavelengths of any known crystal and also exhibits a particularly large birefringence and high dispersion. Owing to these properties, it is useful for the manufacture of certain optical elements, especially polarization optics, for longer visible and infrared wavelengths up to about 4.5 micrometres. Natural rutile may contain up to 10% iron and significant amounts of niobium and tantalum. Rutile derives its name from the Latin rutilus ('red'), in reference to the deep red color observed in some specimens when viewed by transmitted light. Rutile was first described in 1803 by Abraham Gottlob Werner using specimens obtained in Horcajuelo de la Sierra, Madrid (Spain), which is consequently the type locality. (Full article...)$

Image 14

Rutile is an oxide mineral composed of titanium dioxide (TiO₂), the most common natural form of TiO₂. Rarer polymorphs of TiO₂ are known, including anatase, akaogiite, and brookite.

Rutile has one of the highest refractive indices at visible wavelengths of any known crystal and also exhibits a particularly large birefringence and high dispersion. Owing to these properties, it is useful for the manufacture of certain optical elements, especially polarization optics, for longer visible and infrared wavelengths up to about 4.5 micrometres. Natural rutile may contain up to 10% iron and significant amounts of niobium and tantalum.

Rutile derives its name from the Latin rutilus ('red'), in reference to the deep red color observed in some specimens when viewed by transmitted light. Rutile was first described in 1803 by Abraham Gottlob Werner using specimens obtained in Horcajuelo de la Sierra, Madrid (Spain), which is consequently the type locality. (Full article...)
Image 15

Micas (/ˈmaɪkəz/ MY-kəz) are a group of silicate minerals whose outstanding physical characteristic is that individual mica crystals can easily be split into fragile elastic plates. This characteristic is described as perfect basal cleavage. Mica is common in igneous and metamorphic rock and is occasionally found as small flakes in sedimentary rock. It is particularly prominent in many granites, pegmatites, and schists, and "books" (large individual crystals) of mica several feet across have been found in some pegmatites.

Micas are used in products such as drywalls, paints, and fillers, especially in parts for automobiles, roofing, and in electronics. The mineral is used in cosmetics and food to add "shimmer" or "frost". (Full article...)
Image 16
The diamond crystal structure belongs to the face-centered cubic lattice, with a repeated two-atom pattern.

In crystallography, a crystal system is a set of point groups (a group of geometric symmetries with at least one fixed point). A lattice system is a set of Bravais lattices (an infinite array of discrete points). Space groups (symmetry groups of a configuration in space) are classified into crystal systems according to their point groups, and into lattice systems according to their Bravais lattices. Crystal systems that have space groups assigned to a common lattice system are combined into a crystal family.

The seven crystal systems are triclinic, monoclinic, orthorhombic, tetragonal, trigonal, hexagonal, and cubic. Informally, two crystals are in the same crystal system if they have similar symmetries (though there are many exceptions). (Full article...)
Image 17

Chalcopyrite (/ˌkælkəˈpaɪˌraɪt, -koʊ-/ KAL-kə-PY-ryte, -⁠koh-) is a copper iron sulfide mineral and the most abundant copper ore mineral. It has the chemical formula CuFeS₂ and crystallizes in the tetragonal system. It has a brassy to golden yellow color and a hardness of 3.5 to 4 on the Mohs scale. Its streak is diagnostic as green-tinged black.

On exposure to air, chalcopyrite tarnishes to a variety of oxides, hydroxides, and sulfates. Associated copper minerals include the sulfides bornite (Cu₅FeS₄), chalcocite (Cu₂S), covellite (CuS), digenite (Cu₉S₅); carbonates such as malachite and azurite, and rarely oxides such as cuprite (Cu₂O). It is rarely found in association with native copper. Chalcopyrite is a conductor of electricity.

Copper can be extracted from chalcopyrite ore using various methods. The two predominant methods are pyrometallurgy and hydrometallurgy, the former being the most commercially viable. (Full article...)
$Image 18 A rough diamond Diamond is a solid form of the element carbon with its atoms arranged in a crystal structure called diamond cubic. Diamond is tasteless, odorless, strong, brittle solid, colorless in pure form, a poor conductor of electricity, and insoluble in water. Another solid form of carbon known as graphite is the chemically stable form of carbon at room temperature and pressure, but diamond is metastable and converts to it at a negligible rate under those conditions. Diamond has the highest hardness and thermal conductivity of any natural material, properties that are used in major industrial applications such as cutting and polishing tools. Because the arrangement of atoms in diamond is extremely rigid, few types of impurity can contaminate it (two exceptions are boron and nitrogen). Small numbers of defects or impurities (about one per million of lattice atoms) can color a diamond blue (boron), yellow (nitrogen), brown (defects), green (radiation exposure), purple, pink, orange, or red. Diamond also has a very high refractive index and a relatively high optical dispersion. Most natural diamonds have ages between 1 billion and 3.5 billion years. Most were formed at depths between 150 and 250 kilometres (93 and 155 mi) in the Earth's mantle, although a few have come from as deep as 800 kilometres (500 mi). Under high pressure and temperature, carbon-containing fluids dissolved various minerals and replaced them with diamonds. Much more recently (hundreds to tens of million years ago), they were carried to the surface in volcanic eruptions and deposited in igneous rocks known as kimberlites and lamproites. Synthetic diamonds can be grown from high-purity carbon under high pressures and temperatures or from hydrocarbon gases by chemical vapor deposition (CVD). Natural and synthetic diamonds are most commonly distinguished using optical techniques or thermal conductivity measurements. (Full article...)$

Image 18

A rough diamond

Diamond is a solid form of the element carbon with its atoms arranged in a crystal structure called diamond cubic. Diamond is tasteless, odorless, strong, brittle solid, colorless in pure form, a poor conductor of electricity, and insoluble in water. Another solid form of carbon known as graphite is the chemically stable form of carbon at room temperature and pressure, but diamond is metastable and converts to it at a negligible rate under those conditions. Diamond has the highest hardness and thermal conductivity of any natural material, properties that are used in major industrial applications such as cutting and polishing tools.

Because the arrangement of atoms in diamond is extremely rigid, few types of impurity can contaminate it (two exceptions are boron and nitrogen). Small numbers of defects or impurities (about one per million of lattice atoms) can color a diamond blue (boron), yellow (nitrogen), brown (defects), green (radiation exposure), purple, pink, orange, or red. Diamond also has a very high refractive index and a relatively high optical dispersion.

Most natural diamonds have ages between 1 billion and 3.5 billion years. Most were formed at depths between 150 and 250 kilometres (93 and 155 mi) in the Earth's mantle, although a few have come from as deep as 800 kilometres (500 mi). Under high pressure and temperature, carbon-containing fluids dissolved various minerals and replaced them with diamonds. Much more recently (hundreds to tens of million years ago), they were carried to the surface in volcanic eruptions and deposited in igneous rocks known as kimberlites and lamproites.

Synthetic diamonds can be grown from high-purity carbon under high pressures and temperatures or from hydrocarbon gases by chemical vapor deposition (CVD). Natural and synthetic diamonds are most commonly distinguished using optical techniques or thermal conductivity measurements. (Full article...)
Image 19

Three varieties of beryl (left to right): morganite, aquamarine and emerald

Beryl (/ˈbɛrəl/ BERR-əl) is a mineral composed of beryllium aluminium silicate with the chemical formula Be₃Al₂(SiO₃)₆. Well-known varieties of beryl include emerald and aquamarine. Naturally occurring hexagonal crystals of beryl can be up to several meters in size, but terminated crystals are relatively rare. Pure beryl is colorless, but it is frequently tinted by impurities; possible colors are green, blue, yellow, pink, and red (the rarest). It is an ore source of beryllium. (Full article...)
Image 20

Galena with minor pyrite

Galena, also called lead glance, is the natural mineral form of lead(II) sulfide (PbS). It is the most important ore of lead and an important source of silver.

Galena is one of the most abundant and widely distributed sulfide minerals. It crystallizes in the cubic crystal system often showing octahedral forms. It is often associated with the minerals sphalerite, calcite and fluorite.

As a pure specimen held in the hand, under standard temperature and pressure, galena is insoluble in water and so is almost non-toxic. Handling galena under these specific conditions (such as in a museum or as part of geology instruction) poses practically no risk; however, as lead(II) sulfide is reasonably reactive in a variety of environments, it can be highly toxic if swallowed or inhaled, particularly under prolonged or repeated exposure. (Full article...)
$Image 21 Talc, or talcum, is a clay mineral composed of hydrated magnesium silicate, with the chemical formula Mg3Si4O10(OH)2. Talc in powdered form, often combined with corn starch, is used as baby powder. This mineral is used as a thickening agent and lubricant. It is an ingredient in ceramics, paints, and roofing material. It is a main ingredient in many cosmetics. It occurs as foliated to fibrous masses, and in an exceptionally rare crystal form. It has a perfect basal cleavage and an uneven flat fracture, and it is foliated with a two-dimensional platy form. The Mohs scale of mineral hardness, based on scratch hardness comparison, defines value 1 as the hardness of talc, the softest mineral. When scraped on a streak plate, talc produces a white streak, though this indicator is of little importance, because most silicate minerals produce a white streak. Talc is translucent to opaque, with colors ranging from whitish grey to green with a vitreous and pearly luster. Talc is not soluble in water, and is slightly soluble in dilute mineral acids. Soapstone is a metamorphic rock composed predominantly of talc. (Full article...)$

Image 21

Talc, or talcum, is a clay mineral composed of hydrated magnesium silicate, with the chemical formula Mg₃Si₄O₁₀(OH)₂. Talc in powdered form, often combined with corn starch, is used as baby powder. This mineral is used as a thickening agent and lubricant. It is an ingredient in ceramics, paints, and roofing material. It is a main ingredient in many cosmetics. It occurs as foliated to fibrous masses, and in an exceptionally rare crystal form. It has a perfect basal cleavage and an uneven flat fracture, and it is foliated with a two-dimensional platy form.

The Mohs scale of mineral hardness, based on scratch hardness comparison, defines value 1 as the hardness of talc, the softest mineral. When scraped on a streak plate, talc produces a white streak, though this indicator is of little importance, because most silicate minerals produce a white streak. Talc is translucent to opaque, with colors ranging from whitish grey to green with a vitreous and pearly luster. Talc is not soluble in water, and is slightly soluble in dilute mineral acids.

Soapstone is a metamorphic rock composed predominantly of talc. (Full article...)
Image 22

A ruby crystal from Dodoma Region, Tanzania

Ruby is a pinkish-red to blood-red gemstone, a variety of the mineral corundum (aluminium oxide). Ruby is one of the most popular traditional jewelry gems and is very durable. Other varieties of gem-quality corundum are called sapphires; given that the rest of the corundum species are called as such, rubies are sometimes referred to as "red sapphires".

Ruby is one of the traditional cardinal gems, alongside amethyst, sapphire, emerald, and diamond. The word ruby comes from ruber, Latin for red. The color of a ruby is due to the presence of chromium.

Some gemstones that are popularly or historically called rubies, such as the Black Prince's Ruby in the British Imperial State Crown, are actually spinels. These were once known as "Balas rubies".

The quality of a ruby is determined by its color, cut, and clarity, which, along with carat weight, affect its value. The brightest and most valuable shade of red, called blood-red or pigeon blood, commands a large premium over other rubies of similar quality. After color comes clarity: similar to diamonds, a clear stone will command a premium, but a ruby without any needle-like rutile inclusions may indicate that the stone has been treated. Ruby is the traditional birthstone for July and is usually pinker than garnet, although some rhodolite garnets have a similar pinkish hue to most rubies. The world's most valuable ruby to be sold at auction is the Estrela de Fura, which sold for US$34.8 million. (Full article...)
Image 23

Amethyst cluster from Artigas, Uruguay

Amethyst is a violet variety of quartz. The name comes from the Koine Greek αμέθυστος amethystos from α- a-, "not" and μεθύσκω (Ancient Greek) methysko / μεθώ metho (Modern Greek), "intoxicate", a reference to the belief that the stone protected its owner from drunkenness. Ancient Greeks wore amethyst and carved drinking vessels from it in the belief that it would prevent intoxication.

Amethyst, a semiprecious stone, is often used in jewelry.

It occurs mostly in association with calcite, quartz, smoky quartz, hematite, pyrite, fluorite, goethite, agate and chalcedony. (Full article...)
Image 24

A sample of andesite (dark groundmass) with amygdaloidal vesicles filled with zeolite. Diameter of view is 8 cm.

Andesite (/ˈændəzaɪt/) is a volcanic rock of intermediate composition. In a general sense, it is the intermediate type between silica-poor basalt and silica-rich rhyolite. It is fine-grained (aphanitic) to porphyritic in texture, and is composed predominantly of sodium-rich plagioclase plus pyroxene or hornblende.

Andesite is the extrusive equivalent of plutonic diorite. Characteristic of subduction zones, andesite represents the dominant rock type in island arcs. The average composition of the continental crust is andesitic. Along with basalts, andesites are a component of the Martian crust.

The name andesite is derived from the Andes mountain range, where this rock type is found in abundance. It was first applied by Christian Leopold von Buch in 1826. (Full article...)
Image 25
A rock containing three crystals of pyrite (FeS₂). The crystal structure of pyrite is primitive cubic, and this is reflected in the cubic symmetry of its natural crystal facets.

In crystallography, the cubic (or isometric) crystal system is a crystal system where the unit cell is in the shape of a cube. This is one of the most common and simplest shapes found in crystals and minerals.

There are three main varieties of these crystals:
- Primitive cubic (abbreviated cP and alternatively called simple cubic)
- Body-centered cubic (abbreviated cI or bcc)
- Face-centered cubic (abbreviated cF or fcc)
Note: the term fcc is often used in synonym for the cubic close-packed or ccp structure occurring in metals. However, fcc stands for a face-centered cubic Bravais lattice, which is not necessarily close-packed when a motif is set onto the lattice points. E.g. the diamond and the zincblende lattices are fcc but not close-packed.
Each is subdivided into other variants listed below. Although the unit cells in these crystals are conventionally taken to be cubes, the primitive unit cells often are not. (Full article...)

List of selected articles

Selected mineralogist

Image 1

Marble relief of Schrauf in the Arkadenhof, University of Vienna

Albrecht Schrauf (14 December 1837, Vienna – 29 November 1897, Vienna) was an Austrian mineralogist and crystallographer. (Full article...)
Image 2
Rudolf Koechlin (11 November 1862 – 11 February 1939) was an Austrian mineralogist.

Koechlin was born and died in Vienna. He studied mineralogy, crystallography, petrology and geology at the University of Vienna, obtaining his doctorate in 1887 with a thesis on manganite, polianite and pyrolusite. At Vienna, his instructors included Gustav Tschermak and Albrecht Schrauf. In 1884 he began work as a volunteer in the mineralogical-petrography department of the Naturhistorisches Hofmuseum in Vienna. In 1897 he became a "custos-adjunct", later named a curator first-class (1912), and in 1920, was appointed director of the mineralogical-petrography department. (Full article...)
Image 3
John Sinkankas (May 15, 1915 – May 17, 2002) was a Navy officer and aviator, gemologist, gem carver and gem faceter, author of many books and articles on minerals and gemstones, and a bookseller and bibliographer of rare books. (Full article...)
Image 4
Adolf Pabst (30 November 1899, Chicago – 3 April 1990, Berkeley, California) was an American mineralogist and geologist. (Full article...)
Image 5
Peter John Wyllie (born 8 February 1930, in London, England) is a British petrologist and academic.

He was Professor of Geology at the California Institute of Technology from 1983 until his retirement in 1999. Prior to this, he held positions at the University of St Andrews (1955–56), Pennsylvania State University (1958–59 and 1961–66), the University of Leeds (1959–61), and the University of Chicago (1965–83). He is well known for his many contributions to the understanding of magmatism, particularly through his work on the experimental petrology of magmas and volatiles. In the early 1970s, Wyllie wrote two widely used textbooks; The Dynamic Earth (1971) and The Way the Earth Works (1976) which integrated the new understanding of magmatism and plate tectonics. He is also famous for his contributions to the coverage of earth sciences in the Encyclopædia Britannica, particularly his outline of the field in Part Two of the Propædia. Wyllie was President of the International Union of Geodesy and Geophysics (IUGG) from 1995 to 1999. (Full article...)
Image 6
Hans Peter Eugster (November 19, 1925, in Igis, Switzerland – December 17, 1987, in Baltimore, US) was a Swiss-American geochemist, mineralogist, and petrologist. (Full article...)
Image 7

Portrait of Marshall McDonald

Marshall McDonald (October 18, 1835 – September 1, 1895) was an American engineer, geologist, mineralogist, pisciculturist, and fisheries scientist. McDonald served as the commissioner of the United States Commission of Fish and Fisheries from 1888 until his death in 1895. He is best known for his inventions of a number of fish hatching apparatuses and a fish ladder that enabled salmon and other migrating fish species to ascend the rapids of watercourses resulting in an increased spawning ground. McDonald's administration of the U.S. Commission of Fish and Fisheries was notably free of scandal and furthered the "protection and culture" of fish species throughout the United States.

Born in 1835 in Romney, Virginia (present-day West Virginia), McDonald was the son of Angus William McDonald, a military officer and lawyer, and his wife, Leacy Anne Naylor. From 1854 to 1855, McDonald studied natural history under Spencer Fullerton Baird at the Smithsonian Institution in Washington, D.C. He then attended the University of Virginia and Virginia Military Institute, from which he graduated in 1860. McDonald served as an assistant professor of chemistry at the institute under Stonewall Jackson and continued to teach intermittently throughout the American Civil War. (Full article...)
Image 8
Frank Thomas Matthews White (16 September 1909 – 26 November 1971) was an Australian mineral engineering educator. His career included roles in Australia, Fiji, Malaysia, and Canada. Following industry appointments in Australia, he established the Fiji Department of Mines, lead the post-War rehabilitation of Malayan tin mines, founded the Department of Mining and Metallurgical Engineering at University of Queensland (UQ), was instrumental in founding International House, University of Queensland, and chaired the Department of Mining Engineering and Applied Geophysics at McGill University, Canada. (Full article...)
Image 9
Hans Schneiderhöhn (2 June 1887 in Mainz – 5 August 1962 in Sölden) was a German geologist and mineralogist who specialized in ore microscopy. (Full article...)
Image 10

Adolph Knopf (December 2, 1882 – November 23, 1966) was an American geologist. Educated at the University of California, Berkeley, he held professional appointments at the United States Geological Survey, Yale University, and Stanford University. He was primarily a petrologist and mineralogist, though later in his career contributed to geochronology. He performed much of his field work in the western United States, investigating mineral deposits in Alaska, the Boulder Batholith in Montana, and the Gold Country of California.

Knopf was a member of the National Academy of Sciences and the American Academy of Arts and Sciences. He served as president of the Geological Society of America in 1944 and received its Penrose Medal in 1959. His second wife, Eleanora Knopf, was a notable geologist and frequent collaborator. (Full article...)
Image 11
József Sándor Krenner or Joseph Krenner (3 March 1839 – 6 January 1920) was a Hungarian mineralogist. He discovered several new minerals.

Krenner was born in Buda and studied at the University of Pest, Vienna and Tübingen mineralogy and geology. He received his Ph.D. in 1865 for work with Friedrich August Quenstedt in Tübingen. Krenner worked in the mineralogy section of the Hungarian National Museum. From 1870 on he also lectured at the Technical University of Budapest. In 1888 he became a member of the Hungarian Academy of Science.
Krenner discovered several new minerals, for example, Krennerite which he discovered in 1877 in Sacaramb, Romania. The mineral is obviously named after himself. Another mineral he discovered was Semseyite, the lead antimony sulfide discovered in 1881 was named after Andor Semsey (1833–1923), a Hungarian nobleman and mineralogist. (Full article...)
Image 12

Hawthorne in 2010

Frank Christopher Hawthorne (born 8 January 1946) is an English-born Canadian mineralogist, crystallographer and spectroscopist. He works at the University of Manitoba and is currently distinguished professor emeritus. By combining graph theory, bond-valence theory and the moments approach to the electronic energy density of solids he has developed bond topology as a rigorous approach to understanding the atomic arrangements, chemical compositions and paragenesis of complex oxide and oxysalt minerals. (Full article...)
Image 13

William Gregor (1761–1817)

William Gregor (25 December 1761 – 11 June 1817) was a British clergyman and mineralogist who discovered the elemental metal Titanium. (Full article...)
Image 14

Tellef Dahll (10 April 1825, in Kragerø – 17 June 1893, in Morgedal) was a Norwegian mineralogist and geologist. (Full article...)
Image 15
François Pierre Nicolas Gillet de Laumont (28 May 1747 – 1 June 1834) was a French mineralogist.

He was born in Paris, educated at a military school and served in the army from 1772 to 1784, when he was appointed inspector of mines. His attention in his leisure time was wholly given to mineralogy, and he assisted in organizing the new École des Mines in Paris. (Full article...)
Image 16

Petru Poni (4 January 1841 – 2 April 1925) was a Romanian chemist and mineralogist.

Born into a family of răzeși (free peasants) in Săcărești, Iași County, he attended primary school in Târgu Frumos. In 1852, he enrolled in Academia Mihăileană; among his teachers were August Treboniu Laurian and Simion Bărnuțiu. He entered the University of Paris in 1865, studying chemistry there. He returned home following graduation, teaching physics and chemistry at Iași's National College and at the military high school. In 1878, he became a professor at the University of Iași, at first teaching at the medicine and science faculties, later only in the mineral chemistry department of the latter. He served as Religious Affairs and Education Minister three times: in 1891, 1895–1896 and in 1918. A bitter rival of his was the Conservative Titu Maiorescu, and he was obliged to leave the Liberal cabinet in 1896 after a dispute related to the Romanian Orthodox Church. When not in government, he continued to work in his chemistry laboratory in Iași. (Full article...)
Image 17
Westgarth Forster (1772–1835) was a geologist and mining engineer, mine agent at Allenheads and Coalcleugh (Northumberland) over two decades and then a consultant surveyor and author. He was the son of a mining engineer, Westgarth Forster the elder, and was born in Coalcleugh, Northumberland. (Full article...)
$Image 18 Gregori Aminoff (8 February 1883 – 11 February 1947) was a Swedish mineralogist, artist, and a member of the Aminoff family. During his career, Aminoff introduced X-ray diffraction and electron diffraction to the Swedish scientific community and was a pioneer in crystallography in Sweden. (Full article...)$

Image 18

Gregori Aminoff (8 February 1883 – 11 February 1947) was a Swedish mineralogist, artist, and a member of the Aminoff family. During his career, Aminoff introduced X-ray diffraction and electron diffraction to the Swedish scientific community and was a pioneer in crystallography in Sweden. (Full article...)
Image 19
Friedrich Rinne

Friedrich Wilhelm Berthold Rinne (16 March 1863 in Osterode am Harz – 12 March 1933 in Freiburg im Breisgau) was a German mineralogist, crystallographer and petrographer. (Full article...)
Image 20
Ferruccio Zambonini (17 December 1880 – 12 January 1932) was an Italian mineralogist and geologist. Most of his time he worked on the geology and mineralogy of Mount Vesuvius. (Full article...)
Image 21
François Alluaud (21 September 1778, Limoges – 18 February 1866, Limoges) was a French manufacturer of Limoges porcelain, geologist and mineralogist. He was the grandfather of entomologist Charles Alluaud (1861–1949).

Following the death of his father in 1799, who was also named François Alluaud, he took over ownership of the family porcelain factory in Limoges. The company operated its own quarries; a feldspar mine at Chanteloube and a kaolin quarry at Marcognac. (Full article...)
Image 22
Bernard (Bernie) Wood is a British geologist, and professor of mineralogy and senior research fellow at the University of Oxford. He specializes in the thermodynamics of geological systems, using experimental techniques. He is a prominent figure in the field of experimental petrology, having received multiple awards throughout his career and taught at several universities worldwide. (Full article...)
Image 23
Wolfgang Sartorius von Waltershausen

Wolfgang Sartorius Freiherr von Waltershausen (17 December 1809 – 16 March 1876) was a German geologist. (Full article...)
Image 24
Charles-Louis de la Vallée Poussin

Charles-Louis-Joseph-Xavier de la Vallée Poussin (6 April 1827, Namur – 15 March 1903, Brussels) was a Belgian geologist and mineralogist. His son was the mathematician Charles Jean de la Vallée Poussin. (Full article...)
Image 25
Louis Jean-Pierre Cabri (born February 23, 1934, in Cairo) is an eminent Canadian scientist in the field of platinum group elements (PGE) mineralogy with expertise in precious metal mineralogy and base metals at the Canada Centre for Mineral and Energy Technology (CANMET). First as research scientist and later as principal scientist (1996–1999). In the 1970s he discovered two new Cu–Fe sulfide minerals, "mooihoekite" and "haycockite". In 1983 Russian mineralogists named a new mineral after him: cabriite (Pd₂SnCu). (Full article...)

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... that nine days after his heart transplant, J. C. Walter Jr. merged his company Houston Oil & Minerals with Tenneco, then retired to his ranch and shortly after founded Walter Oil & Gas?

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General images

The following are images from various mineral-related articles on Wikipedia.

Image 1Natrolite is a mineral series in the zeolite group; this sample has a very prominent acicular crystal habit. (from Mineral)
Image 2Red cinnabar (HgS), a mercury ore, on dolomite. (from Mineral)
Image 3Muscovite, a mineral species in the mica group, within the phyllosilicate subclass (from Mineral)
Image 4Pyrite (from Lustre (mineralogy))
Image 5Aegirine, an iron-sodium clinopyroxene, is part of the inosilicate subclass. (from Mineral)
Image 6Perfect basal cleavage as seen in biotite (black), and good cleavage seen in the matrix (pink orthoclase). (from Mineral)
Image 7Contact twins, as seen in spinel (from Mineral)
Image 8Gypsum desert rose (from Mineral)
Image 9Asbestiform tremolite, part of the amphibole group in the inosilicate subclass (from Mineral)
Image 10Black andradite, an end-member of the orthosilicate garnet group. (from Mineral)
Image 11Mohs hardness kit, containing one specimen of each mineral on the ten-point hardness scale (from Mohs scale)
Image 12Galena, PbS, is a mineral with a high specific gravity. (from Mineral)
Image 13Sphalerite crystal partially encased in calcite from the Devonian Milwaukee Formation of Wisconsin (from Mineral)
Image 14When minerals react, the products will sometimes assume the shape of the reagent; the product mineral is termed a pseudomorph of (or after) the reagent. Illustrated here is a pseudomorph of kaolinite after orthoclase. Here, the pseudomorph preserved the Carlsbad twinning common in orthoclase. (from Mineral)
Image 15Native gold. Rare specimen of stout crystals growing off of a central stalk, size 3.7 x 1.1 x 0.4 cm, from Venezuela. (from Mineral)
Image 16Pink cubic halite (NaCl; halide class) crystals on a nahcolite matrix (NaHCO₃; a carbonate, and mineral form of sodium bicarbonate, used as baking soda). (from Mineral)
Image 17Crystals of serandite, natrolite, analcime, and aegirine from Mont Saint-Hilaire, Quebec, Canada (from Mineral)
Image 18An example of elbaite, a species of tourmaline, with distinctive colour banding. (from Mineral)
Image 19Carnotite (yellow) is a radioactive uranium-bearing mineral. (from Mineral)
Image 20Pyrite has a metallic lustre. (from Mineral)
Image 21Schist is a metamorphic rock characterized by an abundance of platy minerals. In this example, the rock has prominent sillimanite porphyroblasts as large as 3 cm (1.2 in). (from Mineral)
Image 22Mohs Scale versus Absolute Hardness (from Mineral)
Image 23Diamond is the hardest natural material, and has a Mohs hardness of 10. (from Mineral)
Image 24Topaz has a characteristic orthorhombic elongated crystal shape. (from Mineral)
Image 25Epidote often has a distinctive pistachio-green colour. (from Mineral)
Image 26Hübnerite, the manganese-rich end-member of the wolframite series, with minor quartz in the background (from Mineral)

Did you know ...?

... that while bultfonteinite (pictured) was discovered as early as 1903, the mineral wasn't described until 1932?
... that the minerals armalcolite, pyroxferroite and tranquillityite were discovered in lunar rocks?
... that taaffeite, one of the world's rarest gemstones, is the first mineral known to contain both beryllium and magnesium as essential components?
... that the newly discovered mineral krotite likely was one of the earliest minerals formed in the Solar System?

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v t e Minerals
Overview	Mineral Mineralogy History of mineralogy
Common minerals	Amphibole Bridgmanite K-feldspar Mica Olivine Plagioclase Pyroxene Quartz Spinel

v t e Phosphate minerals
Crystalline	Allanpringite Beraunite Brazilianite Eosphorite Fluorapatite Hydroxyapatite Lithiophilite Metatorbernite Monazite Struvite Taranakite Variscite Wavellite Xenotime
Cryptocrystalline	Turquoise Whitlockite
Amorphous	Santabarbaraite Scorodite

v t e Phyllosilicates
Micas	Aluminoceladonite Anandite Annite Aspidolite Balestraite Bityite Biotite Boromuscovite Bramallite Celadonite Chernykhite Chromphyllite Clintonite Eastonite Ephesite Ferroaluminoceladonite Ferroceladonite Fluorannite Fluorokinoshitalite Fluorophlogopite Fluorotetraferriphlogopite Garmite Glauconite Gorbunovite Hendricksite Illite Kinoshitalite Lepidolite Luanshiweiite Manganiceladonite Margarite Masutomilite Montdorite Muscovite Nanpingite Norrishite Orlovite Oxyphlogopite Paragonite Phlogopite Polylithionite Preiswerkite Roscoelite Siderophyllite Suhailite Tainiolite Tetraferriannite Trilithionite Voloshinite Wonesite Yangzhumingite
Talcs	Minnesotaite Talc Willemseite
Pyrophyllite series	Ferripyrophyllite Pyrophyllite
Kaolinites	Bismutoferrite Dickite Halloysite Hisingerite Kaolinite Nacrite
Serpentines	Amesite Antigorite Berthierine Brindleyite Caryopilite Chrysotile Cronstedtite Fraipontite Greenalite Guidottiite Kellyite Lizardite Manandonite Népouite Odinite Pecoraite
Corrensites	Aliettite Brinrobertsite Corrensite Dozyite Hydrobiotite Karpinskite Kulkeite Lunijianlaite Rectorite Saliotite Tosudite
Smectites and vermiculite family	Beidellite Ferrosaponite Montmorillonite Nontronite Saponite Sauconite Swinefordite Vermiculite Volkonskoite Yakhontovite
Chlorites	Baileychlore Borocookeite Chamosite Clinochlore Cookeite Donbassite Gonyerite Nimite Pennantite Sudoite
Allophanes	Allophane Chrysocolla Imogolite Neotocite
Sepiolites	Falcondoite Ferrisepiolite Sepiolite
Pyrosmalites	Friedelite Mcgillite Nelenite Pyrosmalite Schallerite
Stilpnomelanes	Bannisterite Franklinphilite Lennilenapeite Parsettensite Stilpnomelane
Structural groups mainly; based on rruff.info/ima, modified

v t e IMA–CNMNC / Nickel–Strunz IDs Mineral categories (classes, subclasses, divisions)
"Special cases" ("native elements and organic minerals")	"Native elements" (IDs 1) Organic minerals (IDs 10)
"Sulfides and oxides"	Sulfides (IDs 2.A–F) Sulfosalts; sulfarsenites, sulfantimonites, sulfbismuthites (IDs 2.G) Sulfosalts; sulfarsenates, sulfantimonates (IDs 2.K) Other sulfosalts (IDs 2.H–J and 2.L–M) Oxides (IDs 4.A–E, e.g. pyrochlore supergroup and corundum group) Hydroxides (IDs 4.F–G) Arsenates(IV), sulfates(IV) and iodates (IDs 4.J–K) Tellurium oxysalts Vanadium oxides (IDs 4.H)
"Evaporites and similars"	Carbonates (IDs 5.A–E) Nitrates (IDs 5.N) Borates (IDs 6) Halides (IDs 3)
"Mineral structures with tetrahedral units" (sulfate anion, phosphate anion, silicon, etc.)	Monomeric minerals (similar to nesosilicates) Sulfates(VI) (IDs 7.A–E) Thiosulphates (IDs 7.J) Chromates(VI) (IDs 7.F) Molybdates, wolframates, niobates(VI) (IDs 7.G–H) Phosphates(V) (IDs 8) Arsenates, vanadates(V) (IDs 8) Monomeric, isolated silicates (IDs 9.A) Germanates (IDs 9.J) Silicate frameworks, tectosilicates Zeolite frameworks, zeolite family (IDs 9.G) Other feldspathoids: nephelines (IDs 9.FA.05) Cancrinite-sodalite groups (IDs 9.FB.) Other tectosilicates (IDs 9.FA. and 9.FB.15, e.g. feldspars) Other silicate frameworks Cyclosilicates (IDs 9.C) Phyllosilicates (IDs 9.E, e.g. clays) Silica family (IDs 4.DA.) Inosilicates Single chain inosilicates (IDs 9.D, e.g. pyroxenes) Ribbon or multiple chain inosilicates (IDs 9.D, e.g. amphiboles) Other non monomeric minerals Unclassified silicates (IDs 9.H) Sorosilicates (IDs 9.B, e.g. epidote and seidozerite supergroups) Polymeric, isolated silicates (IDs 9.A, e.g. olivine and gadolinite supergroups) Other inorganic polymers (e.g. polyoxometalates; "polyphosphates", IDs 8.F)