Portal:Minerals

Crystallography is the experimental science of determining the arrangement of atoms in crystalline solids. Crystallography is a fundamental subject in the fields of materials science and solid-state physics (condensed matter physics). The word crystallography is derived from the Ancient Greek word κρύσταλλος (krústallos; "clear ice, rock-crystal"), with its meaning extending to all solids with some degree of transparency, and γράφειν (gráphein; "to write"). In July 2012, the United Nations recognised the importance of the science of crystallography by proclaiming that 2014 would be the International Year of Crystallography.

Before the development of X-ray diffraction crystallography (see below), the study of crystals was based on physical measurements of their geometry using a goniometer. This involved measuring the angles of crystal faces relative to each other and to theoretical reference axes (crystallographic axes), and establishing the symmetry of the crystal in question. The position in 3D space of each crystal face is plotted on a stereographic net such as a Wulff net or Lambert net. The pole to each face is plotted on the net. Each point is labelled with its Miller index. The final plot allows the symmetry of the crystal to be established.

Crystallographic methods now depend on analysis of the diffraction patterns of a sample targeted by a beam of some type. X-rays are most commonly used; other beams used include electrons or neutrons. Crystallographers often explicitly state the type of beam used, as in the terms X-ray crystallography, neutron diffraction and electron diffraction. These three types of radiation interact with the specimen in different ways.

• X-rays interact with the spatial distribution of electrons in the sample.
• Electrons are charged particles and therefore interact with the total charge distribution of both the atomic nuclei and the electrons of the sample.
• Neutrons are scattered by the atomic nuclei through the strong nuclear forces, but in addition, the magnetic moment of neutrons is non-zero. They are therefore also scattered by magnetic fields. When neutrons are scattered from hydrogen-containing materials, they produce diffraction patterns with high noise levels. However, the material can sometimes be treated to substitute deuterium for hydrogen. Because of these different forms of interaction, the three types of radiation are suitable for different crystallographic studies.

The following sections mainly describe the use of X-rays. See these links for further information on using electrons for diffraction, crystallographic imaging, in transmission, reflection or for surfaces. For addition details on using neutrons see neutron diffraction. (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. It is commonly used as an abrasive on sandpaper and on large tools used in machining metals, plastics, and wood. Emery, a variety of corundum with no value as a gemstone, is commonly used as an abrasive. 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...)

A ruby crystal from Dodoma Region, Tanzania

A 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. 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 element 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 follows 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 Sunrise Ruby. (Full article...)

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. (Full article...)

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 lenses have low dispersion, so lenses made from it exhibit less chromatic aberration, making them valuable in microscopes and telescopes. Fluorite optics are also usable in the far-ultraviolet and mid-infrared ranges, where conventional glasses are too opaque for use. (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...)

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...)

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 unique hue.

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

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...)

Cinnabar (/ˈsɪnəˌbɑːr/; from Ancient Greek κιννάβαρι (kinnábari)), or cinnabarite (/ˌsɪnəˈbɑːraɪt/), 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 recent volcanic activity and alkaline hot springs. The mineral resembles quartz in symmetry and in its exhibiting 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.

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

Magnetite from Iron Bridge, WA.

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...)

Intergrowth of lustrous, cubic crystals of pyrite, with some surfaces showing characteristic striations, from Huanzala mine, Ancash, Peru. Specimen size: 7.0 × 5.0 × 2.5 cm

The mineral pyrite (/ˈpaɪraɪt/), 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 (pyr), '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 we now call pyrite.

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

The slightly misshapen octahedral shape of this rough diamond crystal in matrix is typical of the mineral. Its lustrous faces also indicate that this crystal is from a primary deposit.

Diamond is a solid form of the element carbon with its atoms arranged in a crystal structure called diamond cubic. 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. They are also the reason that diamond anvil cells can subject materials to pressures found deep in the Earth.

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) color 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). Imitation diamonds can also be made out of materials such as cubic zirconia and silicon carbide. Natural, synthetic and imitation diamonds are most commonly distinguished using optical techniques or thermal conductivity measurements. (Full article...)

Graphite specimen

Graphite (/ˈɡræfaɪt/) is a crystalline form of the element carbon. It consists of stacked layers of graphene. Graphite occurs naturally and is the most stable form of carbon under standard conditions. Synthetic and natural graphite are consumed on large scale (300 kton/year, in 1989) for uses in pencils, lubricants, and electrodes. Under high pressures and temperatures it converts to diamond. It is a good (but not excellent) conductor of both heat and electricity. (Full article...)

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 deep under the sea by the compression of microscopic plankton that 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...)

Brazilian trigonal hematite crystal

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 it forms a complete solid solution at temperatures above 950 °C (1,740 °F).

Hematite naturally occurs 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. 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 can 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 can also 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...)

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...)

A lustrous crystal of zircon perched on a tan matrix of calcite from the Gilgit District of Pakistan

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...)

Halite from the Wieliczka salt mine, Małopolskie, Poland

Halite (/ˈhælaɪt, ˈheɪlaɪt/), commonly known as rock salt, is a type of salt, the mineral (natural) form of sodium chloride (NaCl). Halite forms isometric crystals. The mineral is typically colorless or white, but may also be light blue, dark blue, purple, pink, red, orange, yellow or gray depending on inclusion of other materials, impurities, and structural or isotopic abnormalities in the crystals. It commonly occurs with other evaporite deposit minerals such as several of the sulfates, halides, and borates. The name halite is derived from the Ancient Greek word for "salt", ἅλς (háls). (Full article...)

Zeolites are microporous, crystalline aluminosilicate materials 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⁺. These positive ions can be exchanged for others in a contacting electrolyte solution. H⁺
exchanged zeolites are particularly useful as solid acid catalysts.

The term zeolite 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. , 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...)

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 its amorphous property, 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), which means 'to see a change in color'.

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...)

Quartz crystal cluster from Tibet

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 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 Eurasia.

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...)

Kaolinite (/ˈkeɪ.ələˌnaɪt, -lɪ-/ KAY-ə-lə-nyte, -⁠lih-) 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) octahedra.

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 yield white, yellow, or light orange colors. Alternating 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 $US4.24 billion. (Full article...)

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

All species of garnets possess similar physical properties and crystal forms, but differ in chemical composition. The different species are pyrope, almandine, spessartine, grossular (varieties of which are hessonite or cinnamon-stone and tsavorite), uvarovite and andradite. The garnets make up two solid solution series: pyrope-almandine-spessartine (pyralspite), with the composition range [Mg,Fe,Mn]₃Al₂(SiO₄)₃; and uvarovite-grossular-andradite (ugrandite), with the composition range Ca₃[Cr,Al,Fe]₂(SiO₄)₃. (Full article...)

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...)

René Just Haüy

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...)

Johan Afzelius

Johan Afzelius (13 June 1753 in Larv – 20 May 1837 in Uppsala) was a Swedish chemist and notable as the doctoral advisor of one of the founders of modern chemistry, Jöns Jacob Berzelius. He was the brother of botanist Adam Afzelius and physician Pehr von Afzelius.

Afzelius received his PhD at Uppsala University in 1776 under Torbern Olof Bergman. In 1780 he became a lecturer at Uppsala and in 1784 a professor of chemistry. From 1792 to 1797 he undertook research trips to Norway, Denmark and Russia in order to study mineral deposits and to visit scientific institutions. His remarkable mineral collection became part of Uppsala University's mineral cabinet. (Full article...)

Achille Ernest Oscar Joseph Delesse (3 February 1817 – 24 March 1881) was a French geologist and mineralogist. He is credited for inventing the Delesse principle in stereology. (Full article...)

James Sowerby painted by Thomas Heaphy (1816)

James Sowerby (21 March 1757 – 25 October 1822) was an English naturalist, illustrator and mineralogist. Contributions to published works, such as A Specimen of the Botany of New Holland or English Botany, include his detailed and appealing plates. The use of vivid colour and accessible texts were intended to reach a widening audience in works of natural history. The standard author abbreviation Sowerby is used to indicate this person as the author when citing a botanical name.[1] (Full article...)

Christian Ernst Weiss (12 May 1833, in Eilenburg – 4 July 1890, in Schkeuditz) was a German mineralogist, geologist and palaeontologist.
He is not to be confused with the historian Christian Ernst Weiße (1766–1832). (Full article...)

Cover of magazine Hvar 8 dag no. 42, 1906.

Sten Anders Hjalmar Sjögren (13 June 1856, Färnebo, Värmland – 23 March 1922, Stockholm) was a Swedish geologist and mineralogist. (Full article...)

Wolf Jürgen Baron von Engelhardt (9 February 1910, Tartu – 4 December 2008, Tübingen) was a German geologist and mineralogist.

Baron von Engelhardt was a descendant of a Baltic German noble family Engelhardt. (Full article...)

Alexandra Navrotsky with Lee Penn performing the methane mamba chemical demonstration

Alexandra Navrotsky (born 20 June 1943 in New York City) is a physical chemist in the field of nanogeoscience. She is an elected member of the United States National Academy of Sciences (NAS) and the American Philosophical Society (APS). She was a board member of the Earth Sciences and Resources division of the NAS from 1995 until 2000.
In 2005, she was awarded the Urey Medal, by the European Association of Geochemistry.
In 2006, she was awarded the Harry H. Hess Medal, by the American Geophysical Union.
She is currently the director of NEAT ORU (Nanomaterials in Environment, Agriculture, and Technology Organized Research Unit), a primary program in nanogeoscience. She is Distinguished Professor at University of California, Davis. (Full article...)

Vesselina Vassileva Breskovska (Bulgarian: Веселина Василева Бресковска) (December 6, 1928, Granit, Stara Zagora Province, Bulgaria – August 12, 1997, Sofia, Bulgaria) was a 20th-century Bulgarian geologist, mineralogist and crystallographer. (Full article...)

William Alexander (Alex) Deer FRS (26 October 1910 – 8 February 2009) was a distinguished British geologist, petrologist and mineralogist. (Full article...)

Samuel Fowler (October 30, 1779, at Newburgh, Orange County, New York, United States – February 20, 1844, at Franklin, Sussex County, New Jersey) was a doctor, state legislator, and member of the United States House of Representatives from northwestern New Jersey. As the owner of zinc and iron mines and an iron works at Franklin, New Jersey, he became a noted mineralogist who discovered several varieties of rare minerals (chiefly various ores of zinc). (Full article...)

Franz Eugen Geinitz (15 February 1854, Dresden – 9 March 1925, Rostock) was a German geologist and mineralogist best known for his geological studies of the Mecklenburg region. He was the son of geologist Hanns Bruno Geinitz. (Full article...)

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

Franz-Joseph Müller, Freiherr von Reichenstein or Franz-Joseph Müller von Reichenstein (1 July 1740 or 4 October 1742 – 12 October 1825 or 1826) was an Austrian mineralogist and mining engineer. Müller held several positions in the Habsburg monarchy administration of mines and coinage in the Banat, Transylvania, and Tyrol. During his time in Transylvania he discovered tellurium in 1782. In his later career he became a member of the imperial council in Vienna and was knighted and elevated to the rank Freiherr in 1820. (Full article...)

Giuseppe Giovanni Antonio Meneghini (30 July 1811, Padua – 29 January 1889, Pisa) was an Italian botanist, geologist and paleontologist. (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...)

Silliman around 1850

Benjamin Silliman (August 8, 1779 – November 24, 1864) was an early American chemist and science educator. He was one of the first American professors of science, at Yale College, the first person to use the process of fractional distillation in America, and a founder of the American Journal of Science, the oldest continuously published scientific journal in the United States. (Full article...)

Alfred Wilhelm Stelzner (20 December 1840, Dresden – 25 February 1895, Wiesbaden) was a German geologist.

From 1859 to 1864 he was a student at the Bergakademie Freiberg, an institute where he later served as inspector. From 1871 to 1874 he was a professor of mineralogy and geology at the University of Córdoba in Argentina. In 1874 he returned to the Bergakademie at Freiberg, where he succeeded his former teacher, Bernhard von Cotta. Here, he taught classes until his death in 1895. (Full article...)

Robert Miller Hazen (born November 1, 1948) is an American mineralogist and astrobiologist. He is a research scientist at the Carnegie Institution of Washington's Geophysical Laboratory and Clarence Robinson Professor of Earth Science at George Mason University, in the United States. Hazen is the Executive Director of the Deep Carbon Observatory. (Full article...)

Tellef Dahll (10 April 1825, in Kragerø – 17 June 1893, in Morgedal) was a Norwegian mineralogist and geologist. (Full article...)

William Sefton Fyfe, CC FRSC FRS FRSNZ (4 June 1927 – 11 November 2013) was a New Zealand geologist and Professor Emeritus in the department of Earth Sciences at the University of Western Ontario. He is widely considered among the world's most eminent geochemists. (Full article...)

Arthur Connell FRS FRSE (30 November 1794 – 31 October 1863) was a Scottish chemist and mineralogist. The mineral Connellite is named after him. He was a Fellow of the Royal Society of London. (Full article...)

Carlo Perrier (born July 7, 1886, in Turin, † May 22, 1948 in Genoa ) was an Italian mineralogist and chemist who did extensive research on the element technetium. With the discovery of technetium in 1937, he and Emilio Segrè accounted for the last gap in the periodic table. Technetium was the first element produced artificially (hence the name that Segrè and Perrier gave it).

His parents were named Bertolini. Perrier studied chemistry at the Polytechnic in Turin with a Laureate degree in 1908. From 1911 to 1912 he worked at the Laboratory for Physical Chemistry and Electrochemistry at ETH Zurich with Baur and Treadwell. He then worked as an assistant of Arnaldo Piutti at the University of Naples. There he made friends with Ferruccio Zambonini and involved with mineralogy and the study of radioactivity. He was Zambonini's assistant in Turin and, after a competition, became director of the State Geochemical Laboratory in Rome in 1921. In 1927 he completed his habilitation and after another competition became an associate professor in Messina. In 1929 he relocated to Palermo and in 1939 to the University of Genoa. (Full article...)

Friedrich Martin Berwerth (16 November 1850, Schäßburg – 22 September 1918, Vienna) was an Austrian mineralogist and petrographer known for his work with meteorites.

He was a student at the Universities of Vienna, Graz and Heidelberg, and following graduation, worked as an assistant to Gustav Tschermak von Seysenegg at the Mineralogisch-Petrographischen Institut in Vienna (1874). Later the same year, he began work as an assistant at the Imperial Hofmineralien Cabinet. In 1888 he became a curator, followed by titles of leiter (1895) and director (1904) of the mineralogy-petrography department. (Full article...)