Portal:Minerals

Ruby is a pinkish-red-to-blood-red-colored 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...)

Apatite is a group of phosphate minerals, usually hydroxyapatite, fluorapatite and chlorapatite, with high concentrations of OH⁻, F⁻ and Cl⁻ ion, respectively, in the crystal. The formula of the admixture of the three most common endmembers is written as Ca₁₀(PO₄)₆(OH,F,Cl)₂, and the crystal unit cell formulae of the individual minerals are written as Ca₁₀(PO₄)₆(OH)₂, Ca₁₀(PO₄)₆F₂ and Ca₁₀(PO₄)₆Cl₂.

The mineral was named apatite by the German geologist Abraham Gottlob Werner in 1786, although the specific mineral he had described was reclassified as fluorapatite in 1860 by the German mineralogist Karl Friedrich August Rammelsberg. Apatite is often mistaken for other minerals. This tendency is reflected in the mineral's name, which is derived from the Greek word ἀπατάω (apatáō), which means to deceive. (Full article...)

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 new developments in these fields. (Full article...)

Turquoise is an opaque, blue-to-green mineral that is a hydrous phosphate of copper and aluminium, with the chemical formula CuAl₆(PO₄)₄(OH)₈·4H₂O. It is rare and valuable in finer grades and has been prized as a gemstone for millennia due to its hue.

The robin egg blue or sky blue color of the Persian turquoise mined near the modern city of Nishapur, Iran, has been used as a guiding reference for evaluating turquoise quality.

Like most other opaque gems, turquoise has been devalued by the introduction of treatments, imitations, and synthetics into the market. (Full article...)

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...)

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...)

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...)

Asbestos (/æsˈbɛstəs, æz-, -tɒs/ ass-BES-təs, az-, -⁠toss) is a group of naturally occurring, toxic, carcinogenic and fibrous silicate minerals. There are six types, all of which are composed of long and thin fibrous crystals, each fibre (particulate with length substantially greater than width) being composed of many microscopic "fibrils" that can be released into the atmosphere by abrasion and other processes. Inhalation of asbestos fibres can lead to various dangerous lung conditions, including mesothelioma, asbestosis, and lung cancer. As a result of these health effects, asbestos is considered a serious health and safety hazard.

Archaeological studies have found evidence of asbestos being used as far back as the Stone Age to strengthen ceramic pots, but large-scale mining began at the end of the 19th century when manufacturers and builders began using asbestos for its desirable physical properties. Asbestos is an excellent thermal and electrical insulator, and is highly fire-resistant, so for much of the 20th century, it was very commonly used around the world as a building material (particularly for its fire-retardant properties), until its adverse effects on human health were more widely recognized and acknowledged in the 1970s. Many buildings constructed before the 1980s contain asbestos.

The use of asbestos for construction and fireproofing has been made illegal in many countries. Despite this, around 255,000 people are thought to die each year from diseases related to asbestos exposure. In part, this is because many older buildings still contain asbestos; in addition, the consequences of exposure can take decades to arise. The latency period (from exposure until the diagnosis of negative health effects) is typically 20 years. The most common diseases associated with chronic asbestos exposure are asbestosis (scarring of the lungs due to asbestos inhalation) and mesothelioma (a type of cancer).

Many developing countries still support the use of asbestos as a building material, and mining of asbestos is ongoing, with the top producer, Russia, having an estimated production of 790,000 tonnes in 2020. (Full article...)

Magnetite is a mineral and one of the main iron ores, with the chemical formula Fe²⁺Fe3+2O₄. It is one of the oxides of iron, and is ferrimagnetic; it is attracted to a magnet and can be magnetized to become a permanent magnet itself. With the exception of extremely rare native iron deposits, it is the most magnetic of all the naturally occurring minerals on Earth. Naturally magnetized pieces of magnetite, called lodestone, will attract small pieces of iron, which is how ancient peoples first discovered the property of magnetism.

Magnetite is black or brownish-black with a metallic luster, has a Mohs hardness of 5–6 and leaves a black streak. Small grains of magnetite are very common in igneous and metamorphic rocks.

The chemical IUPAC name is iron(II,III) oxide and the common chemical name is ferrous-ferric oxide. (Full article...)

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...)

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...)

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...)

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. (Full article...)

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 assocation with ruby, zircon, biotite, muscovite, calcite, dravite and quartz. (Full article...)

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...)

Cinnabar (/ˈsɪnəˌbɑːr/; from Ancient Greek κιννάβαρι (kinnábari)), or cinnabarite (/ˌsɪnəˈbɑːraɪt/), also known as mercurblende, is the bright scarlet to brick-red form of mercury(II) sulfide (HgS). It is the most common source ore for refining elemental mercury and is the historic source for the brilliant red or scarlet pigment termed vermilion and associated red mercury pigments.

Cinnabar generally occurs as a vein-filling mineral associated with volcanic activity and alkaline hot springs. The mineral resembles quartz in symmetry and it exhibits birefringence. Cinnabar has a mean refractive index near 3.2, a hardness between 2.0 and 2.5, and a specific gravity of approximately 8.1. The color and properties derive from a structure that is a hexagonal crystalline lattice belonging to the trigonal crystal system, crystals that sometimes exhibit twinning.

Cinnabar has been used for its color since antiquity in the Near East, including as a rouge-type cosmetic, in the New World since the Olmec culture, and in China since as early as the Yangshao culture, where it was used in coloring stoneware. In Roman times, cinnabar was highly valued as paint for walls, especially interiors, since it darkened when used outdoors due to exposure to sunlight.

Associated modern precautions for the use and handling of cinnabar arise from the toxicity of the mercury component, which was recognized as early as ancient Rome. (Full article...)

Zircon (/ˈzɜːrkɒn, -kən/) is a mineral belonging to the group of nesosilicates and is a source of the metal zirconium. Its chemical name is zirconium(IV) silicate, and its corresponding chemical formula is ZrSiO₄. An empirical formula showing some of the range of substitution in zircon is (Zr_1–y, REE_y)(SiO₄)_1–x(OH)_4x–y. Zircon precipitates from silicate melts and has relatively high concentrations of high field strength incompatible elements. For example, hafnium is almost always present in quantities ranging from 1 to 4%. The crystal structure of zircon is tetragonal crystal system. The natural color of zircon varies between colorless, yellow-golden, red, brown, blue, and green.

The name derives from the Persian zargun, meaning "gold-hued". This word is changed into "jargoon", a term applied to light-colored zircons. The English word "zircon" is derived from Zirkon, which is the German adaptation of this word. Yellow, orange, and red zircon is also known as "hyacinth", from the flower hyacinthus, whose name is of Ancient Greek origin. (Full article...)

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...)

Malachite (/ˈmæl.əˌkaɪt/) is a copper carbonate hydroxide mineral, with the formula Cu₂CO₃(OH)₂. This opaque, green-banded mineral crystallizes in the monoclinic crystal system, and most often forms botryoidal, fibrous, or stalagmitic masses, in fractures and deep, underground spaces, where the water table and hydrothermal fluids provide the means for chemical precipitation. Individual crystals are rare, but occur as slender to acicular prisms. Pseudomorphs after more tabular or blocky azurite crystals also occur. (Full article...)

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...)

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...)

Quartz is a hard, crystalline 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 mineral in Earth's continental crust, behind feldspar.

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...)

Borax (also referred to as sodium borate, tincal (/ˈtɪŋkəl/) and tincar (/ˈtɪŋkər/)) is a salt (ionic compound) normally encountered as a hydrated borate of sodium, with the chemical formula Na₂H₂₀B₄O₁₇. Borax mineral is a crystalline borate mineral that occurs in only a few places worldwide in quantities that enable it to be mined economically.

Borax can be dehydrated by heating into other forms with less water of hydration. The anhydrous form of borax can also be obtained from the decahydrate or other hydrates by heating and then grinding the resulting glasslike solid into a powder. It is a white crystalline solid that dissolves in water to make a basic solution due to the tetraborate anion.

Borax is commonly available in powder or granular form and has many industrial and household uses, including as a pesticide, as a metal soldering flux, as a component of glass, enamel, and pottery glazes, for tanning of skins and hides, for artificial aging of wood, as a preservative against wood fungus, as a food additive, and as a pharmaceutic alkalizer. In chemical laboratories it is used as a buffering agent.

The terms tincal and tincar refer to the naturally-occurring borax historically mined from dry lake beds in various parts of Asia. (Full article...)

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...)

Diamond is a solid form of the element carbon with its atoms arranged in a crystal structure called diamond cubic. Diamond is tasteless, odourless, strong, brittle solid, colourless 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...)

Anders Jahan Retzius (3 October 1742 – 6 October 1821) was a Swedish chemist, botanist and entomologist. (Full article...)

Warren D. Huff (born April 16, 1937) is Professor of Geology at the University of Cincinnati (UC). He specializes in clay mineralogy, researching the remnants of ancient volcanic eruptions.

He received his BA from Harvard College, 1959 and his PhD from University of Cincinnati, 1963. He has served as assistant professor at UC 1963-1969, associate professor 1969-1985, full professor 1985 to date. He teaches introductory geology sequence. (Full article...)

Charles Louis Christ (March 12, 1916 – June 29, 1980) was an American scientist, geochemist and mineralogist. (Full article...)

Johann Nepomuk von Fuchs (15 May 1774 – 5 March 1856) was a German chemist and mineralogist, and royal Bavarian privy councillor. (Full article...)

Gustaf Flink, born 18 January 1848 in Ås Parish, Skaraborg County, died 11 January 1931, was a Swedish mineralogist.

Flink received training as a primary school teacher and graduated in Gothenburg in 1869. In 1871 he received a teaching position in Stockholm. He accompanied Adolf Erik Nordenskiöld on his expedition to Greenland, during which he collected minerals and petrified plants on Iceland in 1883. He returned to Iceland in 1893. On behalf of a Royal Danish geological and geographical commission he made mineralogical investigations in southern Greenland in 1897. (Full article...)

Cecil Edgar Tilley FRS, Hon FRSE, PGS (14 May 1894 – 24 January 1973) was an Australian-British petrologist and geologist. (Full article...)

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...)

Ullmannite or Nickel glance (trivial name) is a nickel antimony sulfide mineral with formula: NiSbS. Considerable substitution occurs with cobalt and iron in the nickel site along with bismuth and arsenic in the antimony site. A solid solution series exists with the high cobalt willyamite. (Full article...)

Johann Jakob Nöggerath (also as Johann Jacob Noeggerath) (10 October 1788 – 13 September 1877), German mineralogist and geologist, was born at Bonn.

In 1814-1815 he became a commissioner of mines for some of the Rhine provinces, and in 1818 became an associate professor at the newly established University of Bonn. In 1821 he was named a full professor of mineralogy and mining sciences at Bonn, where he also served as director of the university's natural history museum. He obtained a very fine collection of minerals for the museum, was eminently successful as a teacher, and achieved a wide reputation among mining engineers. (Full article...)

Douglas Saxon Coombs CNZM (23 November 1924 – 23 December 2016) was a New Zealand mineralogist and petrologist. (Full article...)

Antonio D'Achiardi (28 November 1839, in Pisa – 10 December 1902, in Pisa) was an Italian geologist, paleontologist and mineralogist known for his mineralogical and paleontological studies of Tuscany. He was the father of the mineralogist Giovanni D'Achiardi [it], and the artist, Pietro D'Achiardi.

In 1859 he received his doctorate in sciences from the University of Pisa, afterwards working as an assistant for chemistry (from 1861). Three months after this appointment, he lost the use of his left eye due to a laboratory accident involving nitric acid. He subsequently abandoned his career in chemistry, and instead devoted his attention to geology and mineralogy, becoming a student of Giuseppe Meneghini. He later became a professor of geology at Pavia and in 1874 was appointed a professor of mineralogy at the University of Pisa. In 1881 he established a laboratory of mineralogy at Pisa. (Full article...)

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...)

Stuart Olof Agrell (5 March 1913 – 29 January 1996) was an optical mineralogist and a pioneer in applications of the electron microprobe to petrology. His involvement as a principal investigator in the analysis of Moon rocks collected in the Apollo program brought him to the attention of the British media and public. (Full article...)

Jean-Baptiste Louis Romé de l'Isle (26 August 1736 – 3 July 1790) was a French mineralogist, considered one of the creators of modern crystallography.

Romé was born in Gray, Haute-Saône, in eastern France. As secretary of a company of artillery in the Carnatic Wars he visited the East Indies, was taken prisoner by the English in 1761, and held in captivity for several years. He was also an alumnus of the Collège Sainte-Barbe in Paris. (Full article...)

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...)

William "Bill" Wallace Pinch (August 15, 1940 – April 1, 2017) was a mineralogist from Rochester, New York. The Mineralogical Association of Canada has an award named after him, the Pinch Medal, "to recognize major and sustained contributions to the advancement of mineralogy by members of the collector-dealer community."
The Pinch Medal has been awarded to a deserving mineralogist every other year since it was first awarded to Pinch in 2001, and is given at the Tucson Mineral Show in February.


Pinch was also a notable mineral collector. His collection was sold in 1989 to the Canadian Museum of Nature for $US 3.5 million, and will be documented in a book to be published in 2018. (Full article...)

James Smithson FRS (c. 1765 – 27 June 1829) was a British chemist and mineralogist. He published numerous scientific papers for the Royal Society during the early 1800s as well as defining calamine, which would eventually be renamed after him as "smithsonite". He was the founding donor of the Smithsonian Institution, which also bears his name.

Born in Paris, France, as the illegitimate child of Elizabeth Hungerford Keate Macie and Hugh Percy (born Hugh Smithson), the 1st Duke of Northumberland, he was given the French name Jacques-Louis Macie. His birth date was not recorded and the exact location of his birth is unknown; it is possibly in the Pentemont Abbey. Shortly after his birth, he naturalised in Britain, where his name was anglicised to James Louis Macie. He adopted his father's original surname of Smithson in 1800, following his mother's death. He attended university at Pembroke College, Oxford in 1782, eventually graduating with a Master of Arts in 1786. As a student he participated in a geological expedition to Scotland and studied chemistry and mineralogy. Highly regarded for his blowpipe analysis and his ability to work in miniature, Smithson spent much of his life traveling extensively throughout Europe; he published some 27 papers in his life. (Full article...)

Oskar Lenz (13 April 1848 in Leipzig – 1 March 1925 in Sooß) was a German-Austrian geologist and mineralogist born in Leipzig. (Full article...)

Marie François Henri Longchambon (27 July 1896 – 20 March 1969) was a French scientist and politician known for his work in geology, particularly on clay minerals, and his role in the French Resistance during World War II. He was awarded the Prix Raulin in 1936 for his scientific contributions. (Full article...)

René Just Haüy (French pronunciation: [aɥi]) FRS MWS FRSE (28 February 1743 – 1 June 1822) was a French priest and mineralogist, commonly styled the Abbé Haüy after he was made an honorary canon of Notre Dame. Due to his innovative work on crystal structure and his four-volume Traité de Minéralogie (1801), he is often referred to as the "Father of Modern Crystallography". During the French Revolution he also helped to establish the metric system. (Full article...)

Hilary Bauerman (16 March 1835 – 5 December 1909) was an English metallurgist, mineralogist and geologist. (Full article...)

Sarah Mawe (1767-1846) was an English mineralogist of the 19th century, appointed to serve Queen Victoria in that capacity from 1837 to 1840. (Full article...)

Frédéric Cailliaud (9 June 1787 – 1 May 1869) was a French naturalist, mineralogist and conchologist. He was born, and died, in Nantes, where he was the curator of the Natural History Museum of Nantes from 1836 to 1869.

He travelled in Egypt, Nubia, and Ethiopia, collecting minerals and making observations. He was a part of the military expedition that his patron Viceroy Muhammad Ali sent south to conquer the Kingdom of Sennar, but also marched further into Fazogli where Caillaud searched for outcroppings of gold while the commander Ismail, son of Muhammad Ali, enslaved locals and slaughtered all who resisted him. Although he failed to find any sizeable deposits of gold in the mountains along the modern Sudan-Ethiopia border, he did make a sufficiently detailed survey of the area to be published after he returned to France in 1827. (Full article...)

Augustin Alexis Damour (19 July 1808, in Paris – 22 September 1902, in Paris) was a French mineralogist who was also interested in prehistory. (Full article...)

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...)