Portal:Minerals

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...)

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...)

Corundum is a crystalline form of aluminium oxide (Al₂O₃) typically containing traces of iron, titanium, vanadium, and chromium. It is a rock-forming mineral. It is a naturally transparent material, but can have different colors depending on the presence of transition metal impurities in its crystalline structure. Corundum has two primary gem varieties: ruby and sapphire. Rubies are red due to the presence of chromium, and sapphires exhibit a range of colors depending on what transition metal is present. A rare type of sapphire, padparadscha sapphire, is pink-orange.

The name "corundum" is derived from the Tamil-Dravidian word kurundam (ruby-sapphire) (appearing in Sanskrit as kuruvinda).

Because of corundum's hardness (pure corundum is defined to have 9.0 on the Mohs scale), it can scratch almost all other minerals. Emery, a variety of corundum with no value as a gemstone, is commonly used as an abrasive on sandpaper and on large tools used in machining metals, plastics, and wood. It is a black granular form of corundum, in which the mineral is intimately mixed with magnetite, hematite, or hercynite.

In addition to its hardness, corundum has a density of 4.02 g/cm³ (251 lb/cu ft), which is unusually high for a transparent mineral composed of the low-atomic mass elements aluminium and oxygen. (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...)

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...)

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, as well as their utilization. (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...)

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...)

Zeolites are a group of several microporous, crystalline aluminosilicate minerals commonly used as commercial adsorbents and catalysts. They mainly consist of silicon, aluminium, 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, 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...)

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...)

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...)

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...)

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...)

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...)

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...)

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...)

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...)

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...)

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...)

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...)

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 silica (SiO₄) linked through oxygen atoms to one octahedral sheet of alumina (AlO₆).

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...)

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...)

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...)

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...)

The mineral pyrite (/ˈpaɪraɪt/ PY-ryte), or iron pyrite, also known as fool's gold, is an iron sulfide with the chemical formula FeS₂ (iron (II) disulfide). Pyrite is the most abundant sulfide mineral.
Pyrite's metallic luster and pale brass-yellow hue give it a superficial resemblance to gold, hence the well-known nickname of fool's gold. The color has also led to the nicknames brass, brazzle, and brazil, primarily used to refer to pyrite found in coal.

The name pyrite is derived from the Greek πυρίτης λίθος (pyritēs lithos), 'stone or mineral which strikes fire', in turn from πῦρ (pŷr), 'fire'. In ancient Roman times, this name was applied to several types of stone that would create sparks when struck against steel; Pliny the Elder described one of them as being brassy, almost certainly a reference to what is now called pyrite.

By Georgius Agricola's time, c. 1550, the term had become a generic term for all of the sulfide minerals. (Full article...)

Christian Samuel Weiss (26 February 1780 – 1 October 1856) was a German mineralogist born in Leipzig.

Following graduation, he worked as a physics instructor in Leipzig from 1803 until 1808. and in the meantime, conducted geological studies of mountain formations in Tyrol, Switzerland and France (1806–08). In 1810 he became a professor of mineralogy at the University of Berlin, where in 1818/19 and 1832/33, he served as university rector. He died near Eger in Bohemia. (Full article...)

James Freeman Dana (born in Amherst, New Hampshire, 23 September 1793; died in New York City, 14 April 1827) was an American chemist. (Full article...)

Morten Thrane Brünnich (30 September 1737 – 19 September 1827) was a Danish zoologist and mineralogist. (Full article...)

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

Johann Gottlob Lehmann (4 August 1719 – 22 January 1767) was a German mineralogist and geologist noted for his work and research contributions to the geologic record leading to the development of stratigraphy. (Full article...)

George Jarvis Brush (December 15, 1831 – February 5, 1912) was an American mineralogist and academic administrator who spent most of his career at Yale University in the Sheffield Scientific School. (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...)

Aristides Brezina (4 May 1848 – 25 May 1909) was an Austrian mineralogist born in Vienna.

In 1872 he graduated from the University of Tübingen, and afterwards taught crystallography at the University of Vienna. In 1878 he succeeded Austrian mineralogist Gustav Tschermak (1836-1927) as custodian of the meteorite collection at Vienna, and from 1889 until 1896 he was director of the Mineralogisch-Petrographische Abteilung (Department of Mineralogy-Petrography). In 1886, he was elected as a member to the American Philosophical Society. (Full article...)

Georg August Goldfuß (18 April 1782 – 2 October 1848) was a German palaeontologist, zoologist and botanist. He became a professor of zoology at the University of Erlangen and later at the University of Bonn. He coined the terms "protozoa" and "pelecypoda". (Full article...)

Georgius Agricola (/əˈɡrɪkələ/; born Georg Bauer; 24 March 1494 – 21 November 1555) was a German Humanist scholar, mineralogist and metallurgist. Born in the small town of Glauchau, in the Electorate of Saxony of the Holy Roman Empire, he was broadly educated, but took a particular interest in the mining and refining of metals. He was the first to drop the Arabic definite article al-, exclusively writing chymia and chymista in describing activity that we today would characterize as chemical or alchemical, giving chemistry its modern name. For his groundbreaking work De Natura Fossilium published in 1546, he is generally referred to as the father of mineralogy and the founder of geology as a scientific discipline.

He is well known for his pioneering work De re metallica libri XII, that was published in 1556, one year after his death. This 12-chapter work is a comprehensive and systematic study, classification and methodical guide on all available factual and practical aspects, that are of concern for mining, the mining sciences and metallurgy, investigated and researched in its natural environment by means of direct observation. Unrivalled in its complexity and accuracy, it served as the standard reference work for two centuries. Agricola stated in the preface, that he will exclude "all those things which I have not myself seen, or have not read or heard of". He continued, "That which I have neither seen, nor carefully considered after reading or hearing of, I have not written about." (Full article...)

Adolf Karl Remelé (17 July 1839, Uerdingen – 16 November 1915, Eberswalde) was a German geologist and mineralogist.

He received his education at the University of Bonn, at the École des Mines in Paris and from the University of Berlin, receiving his doctorate in 1864 with the dissertation "De rubro uranico". In 1867 he qualified as a lecturer at Berlin, and during the following year, succeeded Lothar Meyer at the Forestry Academy in Eberswalde, where he taught classes in chemistry, geognosy and mineralogy. (Full article...)

Joseph Campbell (1856–1933) was an Anglican priest and mineralogist in Australia. Campbell was a recognised authority on geology and served as a consulting engineer in both Queensland and New South Wales. He was an expert on gemstones and wrote several books on the subject. (Full article...)

Ernst Erhard Friedrich Wilhelm Schmid (22 May 1815 in Hildburghausen – 16 February 1885 in Jena) was a German paleontologist. He was the son of law professor Karl Ernst Schmid (1774–1852).

He studied natural sciences at the universities of Jena and Vienna, receiving his doctorate in 1839. In 1843 he became an associate professor at Jena, where with Matthias Jakob Schleiden, he founded a physiological institute. At the institute he dealt with subjects that included mineralogy, geology, chemistry and physics. In 1856 he was appointed a professor of natural sciences at the University of Jena. (Full article...)

Émile Bertrand (1844–1909) was a French mineralogist, in honour of whom bertrandite was named by Alexis Damour. He also gave his name to the Bertrand lens or phase telescope.

He studied at the Ecole des Mines in Paris and was a co-founder of the Société française de minéralogie et de cristallographie. He wrote a book on the application of microscopy to mineralogical studies, "De l'Application du microscope à l'étude de la minéralogie" (1878); published a translation of Ernst Mach's work on the history of mechanics, "La mécanique: exposé historique et critique de son développement" (1904); and is credited with the design of a refractometer. (Full article...)

François Sulpice Beudant (5 September 1787 – 10 December 1850) was a French mineralogist and geologist. The mineral beudantite was named after him. (Full article...)

Stanley Hay Umphray Bowie FRS (born 24 March 1917, in Bixter, Shetland - died 3 September 2008) was a Scottish geologist. He was considered a "world authority on uranium geology and a leader in the field of geochemistry and mineralogy". He developed methods and tools to identify opaque minerals using micro-indentation hardness and optical reflectance. He worked for the British Geological Survey between 1946 and 1977. The mineral bowieite was so named in recognition of his work on identification of opaque minerals. (Full article...)

Werner Schreyer (14 November 1930 in Nuremberg; 12 February 2006 in Bochum) was a German mineralogist and experimental metamorphic petrologist. Schreyer completed his undergraduate work in geology and petrology at the University of Erlangen-Nuremberg, obtained his doctorate from the University of Munich in 1957, and in 1966 received his Habilitation from the University of Kiel. He was a professor at Ruhr University Bochum from 1966 to 1996. In 2002 Schreyer became the first German to be awarded the Mineralogical Society of America's highest honor, the Roebling Medal. Schreyer was a leading expert on phase relations in the MgO–Al₂O₃–SiO₂–H₂O (MASH) system, specializing in cordierite and minerals with equivalent chemical compositions, and high pressure and ultra high-pressure metamorphic mineral assemblages.

The mineral Schreyerite (V2Ti3O9) was named after Schreyer. (Full article...)

Alfred Louis Olivier Legrand Des Cloizeaux (17 October 1817 – 6 May 1897) was a French mineralogist.

Des Cloizeaux was born at Beauvais, in the department of Oise. He studied with Jean-Baptiste Biot at the Collège de France. He became professor of mineralogy at the École Normale Supérieure and afterwards at the Muséum National d'Histoire Naturelle in Paris. He studied the geysers of Iceland, and wrote also on the classification of some of the eruptive rocks. (Full article...)

Vladimir Ivanovich Vernadsky (Russian: Владимир Иванович Вернадский), also spelt Volodymyr Ivanovych Vernadsky (Ukrainian: Володимир Іванович Вернадський; 12 March [O.S. 28 February] 1863 – 6 January 1945), was a Russian, Ukrainian, and Soviet mineralogist and geochemist who is considered one of the founders of geochemistry, biogeochemistry, and radiogeology. He was one of the founders and the first president of the Ukrainian Academy of Sciences (now National Academy of Sciences of Ukraine). Vladimir Vernadsky is most noted for his 1926 book The Biosphere in which he inadvertently worked to popularize Eduard Suess's 1875 term biosphere, by hypothesizing that life is the geological force that shapes the earth. In 1943 he was awarded the Stalin Prize. Vernadsky's portrait is depicted on the Ukrainian ₴1,000 hryvnia banknote. (Full article...)

Edward Daniel Clarke (5 June 1769 – 9 March 1822) was an English clergyman, naturalist, mineralogist, and traveller. (Full article...)

Linus Carl Pauling FRS (/ˈpɔːlɪŋ/ PAW-ling; February 28, 1901 – August 19, 1994) was an American chemist and peace activist. He published more than 1,200 papers and books, of which about 850 dealt with scientific topics. New Scientist called him one of the 20 greatest scientists of all time. For his scientific work, Pauling was awarded the Nobel Prize in Chemistry in 1954. For his peace activism, he was awarded the Nobel Peace Prize in 1962. He is one of five people to have won more than one Nobel Prize. Of these, he is the only person to have been awarded two unshared Nobel Prizes, and one of two people to be awarded Nobel Prizes in different fields, the other being Marie Curie.

Pauling was one of the founders of the fields of quantum chemistry and molecular biology. His contributions to the theory of the chemical bond include the concept of orbital hybridisation and the first accurate scale of electronegativities of the elements. Pauling also worked on the structures of biological molecules, and showed the importance of the alpha helix and beta sheet in protein secondary structure. Pauling's approach combined methods and results from X-ray crystallography, molecular model building, and quantum chemistry. His discoveries inspired the work of Rosalind Franklin, James Watson, Francis Crick, and Maurice Wilkins on the structure of DNA, which in turn made it possible for geneticists to crack the DNA code of all organisms. (Full article...)

Nikolai Semyonovich Kurnakov (Russian: Николай Семёнович Курнаков; 6 December [O.S. 24 November] 1860 – 19 March 1941) was a Russian chemist, who is internationally recognized as the originator of physicochemical analysis. He also was one of the principal founders of the platinum industry in the Soviet Union. A chemical reaction that he pioneered, known as the Kurnakov test, is still used to differentiate cis from trans isomers of divalent platinum and is his best-known contribution to coordination chemistry. (Full article...)

Gustav Anton Zeuner (30 November 1828 – 17 October 1907) was a German physicist, engineer and epistemologist, considered the founder of technical thermodynamics and of the Dresden School of Thermodynamics. (Full article...)

Adolf Knop (12 January 1828, in Altenau – 27 December 1893, in Karlsruhe) was a German geologist and mineralogist.

He studied mathematics and sciences at the University of Göttingen, where he was a pupil of chemist Friedrich Wöhler and mineralogist Johann Friedrich Ludwig Hausmann. From 1849 he taught classes at the vocational school in Chemnitz. In 1857 he became an associate professor of geology and mineralogy at the University of Giessen, where in 1863 he attained a full professorship. In 1866 he relocated to Karlsruhe as a professor at the Polytechnic school. In 1878 he succeeded Moritz August Seubert as manager of the Grand Ducal Natural History Cabinet. (Full article...)

James Reynolds Gregory (29 December 1832 – 15 December 1899) was a noted 19th-century British mineralogist. He founded a mineral specimen business in 1858 which is today known as Gregory, Bottley & Lloyd. Gregory's company had a reputation as one of the best in the business providing mineral samples for scientists as well as private collectors. He primarily bought his specimens at auction or from other collectors and dealers, rarely collecting from the field.

When he was sent in 1868 by diamond merchant Harry Emmanuel of London's Hatton Garden to Hopetown, South Africa, to determine if claims of diamonds being found there were true, he investigated and reported back, that "The whole story of the Cape diamond discoveries is false, and is simply one of the many schemes for trying to promote the employment and expenditure of capital in searching for this pereachous [sic] substance in the colony". (Full article...)