Portal:Minerals
The Minerals Portal
In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid substance with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.
The geological definition of mineral normally excludes compounds that occur only in living organisms. However, some minerals are often biogenic (such as calcite) or organic compounds in the sense of chemistry (such as mellite). Moreover, living organisms often synthesize inorganic minerals (such as hydroxylapatite) that also occur in rocks.
The concept of mineral is distinct from rock, which is any bulk solid geologic material that is relatively homogeneous at a large enough scale. A rock may consist of one type of mineral or may be an aggregate of two or more different types of minerals, spacially segregated into distinct phases.
Some natural solid substances without a definite crystalline structure, such as opal or obsidian, are more properly called mineraloids. If a chemical compound occurs naturally with different crystal structures, each structure is considered a different mineral species. Thus, for example, quartz and stishovite are two different minerals consisting of the same compound, silicon dioxide. (Full article...)
Mineralogy is a subject of geology specializing in the scientific study of the chemistry, crystal structure, and physical (including optical) properties of minerals and mineralized artifacts. Specific studies within mineralogy include the processes of mineral origin and formation, classification of minerals, their geographical distribution, as well as their utilization. (Full article...)
Selected articles
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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. Sapphire is the birthstone for September and the gem of the 45th anniversary. A sapphire jubilee occurs after 65 years. (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...) -
Mineralogy applies principles of chemistry, geology, physics and materials science to the study of minerals
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...) -
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...) -
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...) -
Graphite (/ˈɡræfaɪt/) is a crystalline allotrope (form) of the element carbon. It consists of many stacked layers of graphene, typically in the 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%), lubricants (5%), among others (17%). Under extremely high pressures and extremely high temperatures it converts to diamond. 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...) -
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.
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...) -
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...) -
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 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...) -
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...) -
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...) -
Gypsum is a soft sulfate mineral composed of calcium sulfate dihydrate, with the chemical formula CaSO4·2H2O. It is widely mined and is used as a fertilizer and as the main constituent in many forms of plaster, drywall and blackboard or sidewalk chalk. Gypsum also crystallizes as translucent crystals of selenite. It forms as an evaporite mineral and as a hydration product of anhydrite. The Mohs scale of mineral hardness defines gypsum as hardness value 2 based on scratch hardness comparison.
Fine-grained white or lightly tinted forms of gypsum known as alabaster have been used for sculpture by many cultures including Ancient Egypt, Mesopotamia, Ancient Rome, the Byzantine Empire, and the Nottingham alabasters of Medieval England. (Full article...) -
Green fluorite with prominent cleavage
Cleavage, in mineralogy and materials science, is the tendency of crystalline materials to split along definite crystallographic structural planes. These planes of relative weakness are a result of the regular locations of atoms and ions in the crystal, which create smooth repeating surfaces that are visible both in the microscope and to the naked eye. If bonds in certain directions are weaker than others, the crystal will tend to split along the weakly bonded planes. These flat breaks are termed "cleavage". The classic example of cleavage is mica, which cleaves in a single direction along the basal pinacoid, making the layers seem like pages in a book. In fact, mineralogists often refer to "books of mica".
Diamond and graphite provide examples of cleavage. Each is composed solely of a single element, carbon. In diamond, each carbon atom is bonded to four others in a tetrahedral pattern with short covalent bonds. The planes of weakness (cleavage planes) in a diamond are in four directions, following the faces of the octahedron. In graphite, carbon atoms are contained in layers in a hexagonal pattern where the covalent bonds are shorter (and thus even stronger) than those of diamond. However, each layer is connected to the other with a longer and much weaker van der Waals bond. This gives graphite a single direction of cleavage, parallel to the basal pinacoid. So weak is this bond that it is broken with little force, giving graphite a slippery feel as layers shear apart. As a result, graphite makes an excellent dry lubricant.
While all single crystals will show some tendency to split along atomic planes in their crystal structure, if the differences between one direction or another are not large enough, the mineral will not display cleavage. Corundum, for example, displays no cleavage. (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 as a form of carbon 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. 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) 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...) -
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...) -
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...) -
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...) -
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...) -
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...) -
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...) -
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...) -
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 as gemstone bracelet, tumble, beads, cabochon etc. (Full article...) -
Borax (also referred to as sodium borate, tincal (/ˈtɪŋkəl/) and tincar (/ˈtɪŋkər/)) is a salt (ionic compound), a hydrated or anhydrous borate of sodium, with the chemical formula Na2H20B4O17.
It is a colorless crystalline solid that dissolves in water to make a basic solution.
It 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, and as a pharmaceutic alkalizer. In chemical laboratories, it is used as a buffering agent.
The terms tincal and tincar refer to native borax, historically mined from dry lake beds in various parts of Asia. (Full article...) -
Crystal structure of table salt (sodium in purple, chlorine in green)
In crystallography, crystal structure is a description of ordered arrangement of atoms, ions, or molecules in a crystalline material. Ordered structures occur from 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 material that constitutes this repeating pattern is unit cell of the structure. The unit cell completely reflects symmetry and structure of the entire crystal, which is built up by repetitive translation of unit cell along its principal axes. The translation vectors define the nodes of Bravais lattice.
The lengths of principal axes/edges, of unit cell and angles between them are lattice constants, also called lattice parameters or cell parameters. The symmetry properties of 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...)
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Selected mineralogist
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Arthur Hutchinson OBE FRS (6 July 1866 – 12 December 1937) was a British mineralogist. During World War I, and at the request of the Admiralty, he was asked to design gas masks suitable for the Navy; for his work, he was awarded the OBE. Hutchinson was elected a Fellow of the Royal Society in 1922. He was master of Pembroke College, Cambridge, from 1928 to 1937, served on the Council of the Royal Society from 1932 to 1934, and was the Society's Vice-President for the year 1933-34. (Full article...) -
Ernst Heinrich Oskar Kasimir Weinschenk (6 April 1865, Esslingen am Neckar – 26 March 1921, Munich) was a German mineralogist and petrologist.
He served as a professor at the "Technische Hochschule" in Munich (1897–1921) and at the University of Munich (from 1900). His scientific research included mineralogical analysis of meteorites, and studies of contact-metamorphic mineralization in the Alpine region of central Europe. He also conducted investigations on the origin of the sulfidic ore deposit at Silberberg in the Bavarian Forest, as well as the genesis of graphite deposits near Passau. Through the use of polarizing microscopy and thin sectioning, he determined numerous new minerals. (Full article...) -
The Hope Diamond, which Switzer helped to acquire for the Smithsonian from Harry Winston in 1958
George Shirley Switzer (June 11, 1915 – March 23, 2008) was an American mineralogist who is credited with starting the Smithsonian Institution's famed National Gem and Mineral Collection by acquiring the Hope Diamond for the museum in 1958. Switzer made the arrangements when renowned New York City jeweler Harry Winston decided to donate the Hope Diamond to the Smithsonian.
Switzer was also known for his analysis of Moon rocks which were brought back by NASA missions to the Moon. (Full article...) -
C. E. A. Wichmann
Carl Ernst Arthur Wichmann (9 April 1851 in Hamburg – 28 November 1927 in Hamburg) was a German geologist and mineralogist. He was professor in geology at Utrecht University from 1879 to 1921, where he founded the geological institute. His daughter was the jurist and anarchist-socialist Clara Wichmann, his son the artist and fascist Erich Wichmann.
Arthur Wichmann spent his youth in Hamburg, where his father ran a boarding school. From 1871 to 1874 he studied at Leipzig University, where he was a pupil of Ferdinand Zirkel, from whom he got his interest in mineralogy. After he spent a few years as assistant to Zirkel he became professor at Utrecht University. (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...) -
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-volume 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...) -
Jacques-Louis, Comte de Bournon FRS, FGS (21 January 1751 – 24 August 1825) was a French soldier and mineralogist who came to England after the French Revolution. He gained prominence in the scientific community, being elected a fellow of the Royal Society and was a founding member of the Geological Society before returning to France after the Bourbon Restoration. (Full article...)
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James R. Gregory, circa 1880
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...) -
Ho-Kwang (Dave) Mao (Chinese: 毛河光; pinyin: Máo Héguāng; Wade–Giles: Mao Ho-kuang; born June 18, 1941) is a Chinese-American geologist. He is the director of the Center for High Pressure Science and Technology Advanced Research in Shanghai, China. He was a staff scientist at Geophysical Laboratory of the Carnegie Institution for Science for more than 30 years. Mao is a recognized leading scientist in high pressure geosciences and physical science. There are two minerals named after him, Davemaoite and Maohokite. (Full article...) -
Prof William Hallowes Miller FRS HFRSE LLD DCL (6 April 1801 – 20 May 1880) was a Welsh mineralogist and laid the foundations of modern crystallography.
Miller indices are named after him, the method having been described in his Treatise on Crystallography (1839). The mineral known as millerite is named after him. (Full article...) -
Hilary Bauerman (16 March 1835 – 5 December 1909) was an English metallurgist, mineralogist and geologist. (Full article...)
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Marcel Alexandre Bertrand (2 July 1847 – 13 February 1907) was a French geologist born in Paris. He was the son of mathematician Joseph Louis François Bertrand (1822–1900), and son-in-law to physicist Éleuthère Mascart (1837-1908).
He studied at the École Polytechnique, and beginning in 1869 he attended the Ecole des Mines de Paris. From 1877 he carried out geological mapping studies of Provence, the Jura Mountains and the Alps. In 1886, he became an instructor at the École Nationale Supérieure des Mines, and in 1896 became a member of the Académie des sciences. (Full article...) -
Frederick Augustus Ludwig Karl Wilhelm Genth (May 17, 1820 – February 2, 1893) was a German-American chemist, specializing in analytical chemistry and mineralogy. (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...)
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Wilhelm Karl Ritter von Haidinger (or Wilhelm von Haidinger, or most often Wilhelm Haidinger) (5 February 1795 – 19 March 1871) was an Austrian mineralogist. (Full article...) -
Friedrich Alfred Seifert (born 8 May 1941) is a German mineralogist and geophysicist. He is the founding director of Bayerisches Geoinstitut at University of Bayreuth. A silicate mineral, seifertite, is named after him. (Full article...)
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Augustin-Alexis Damour
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...) -
Fritz Henning Emil Paul Berndt Laves (27 February 1906 – 12 August 1978) was a German crystallographer who served as the president of the German Mineralogical Society from 1956 to 1958. He is the namesake of Laves phases and the Laves tilings; the Laves graph, a highly-symmetrical three-dimensional crystal structure that he studied, was named after him by H. S. M. Coxeter. (Full article...)
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Friedrich Katzer (Czech: Bedřich Katzer; 5 June 1861, Rokitzan – 3 February 1925) was an Austrian geologist and mineralogist.
From 1880 to 1883 he was a student at the University of Prague and at the Technische Hochschule in Prague, where he later worked as an assistant. In 1888 he was head of a testing station for construction materials in Wrschowitz. In 1890 he obtained his PhD from the University of Giessen, later becoming an assistant in mineralogy and geology at the University of Leoben (1892). (Full article...) -
Ian Stuart Edward Carmichael FRS (29 March 1930 –26 August 2011) was a British-born American igneous petrologist and volcanologist who established extensive quantitative methods for research in the thermodynamics of magma. (Full article...)
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Luca Bindi (born 1971) is an Italian geologist. He holds the Chair of Mineralogy and Crystallography and is the Head of the Department of Earth Sciences of the University of Florence. He is also a research associate at the Istituto di Geoscienze e Georisorse of the National Research Council (Italy) (CNR). He has received national and international scientific awards including the 2015 President of the Republic Prize in the category of Physical, Mathematical and Natural Sciences. Since 2019 he has been a Member of the National Academy of Lincei.
He is the Italian scientist who has contributed to the description of the highest number of new minerals and is among the top ten researchers in the world for the number of new mineralogical species described. In his career he has described about 2% of the 6,000 minerals known in nature. Most of the new materials were discovered in the collections of the Museum System of the University of Florence, with its approximately fifty thousand specimens. The researcher is entitled to a further record: among the 150 minerals he described there are 15 extraterrestrials (almost 3% of the 500 discovered), identified in meteorite fragments. (Full article...) -
Konrad Oebbeke (2 November 1853, Hildesheim – 1 February 1932) was a German geologist and mineralogist.
He studied at the Universities of Heidelberg and Erlangen, obtaining his doctorate at the University of Würzburg in 1877. Afterwards he worked as an assistant to the Geological Survey of Bavaria. He served as privat-docent at the University of Munich, later becoming a professor of mineralogy and geology at Erlangen (1887).
From 1895 to 1927 he was a professor at the Technische Hochschule of Munich. (Full article...) -
Gerardus Troost (March 5, 1776 – August 14, 1850) was a Dutch-American medical doctor, naturalist, mineralogist, and founding member and first president of the Philadelphia Academy of Natural Sciences. (Full article...) -
Benjamin Silliman (August 8, 1779 – November 24, 1864) was an 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. He was a founder of the American Journal of Science, the oldest continuously published scientific journal in the United States. (Full article...) -
Der Mineraloge (The Mineralogist) by Raphael Ritz, 1883. Thought to depict the Bonn mineralogist Gerhard vom Rath (1830-1888), examining mineral specimens from Lengenbach in a nearby house in Binn, Switzerland
Gerhard vom Rath (20 August 1830 – 23 April 1888), was a German mineralogist, born at Duisburg in Prussia. (Full article...)
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General images
The following are images from various mineral-related articles on Wikipedia.
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Native gold. Rare specimen of stout crystals growing off of a central stalk, size 3.7 x 1.1 x 0.4 cm, from Venezuela. (from Mineral) -
An example of elbaite, a species of tourmaline, with distinctive colour banding. (from Mineral) -
Hübnerite, the manganese-rich end-member of the wolframite series, with minor quartz in the background (from Mineral) -
Gypsum desert rose (from Mineral) -
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Mohs hardness kit, containing one specimen of each mineral on the ten-point hardness scale (from Mohs scale) -
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Red cinnabar (HgS), a mercury ore, on dolomite. (from Mineral) -
Pyrite (from Lustre (mineralogy)) -
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Sphalerite crystal partially encased in calcite from the Devonian Milwaukee Formation of Wisconsin (from Mineral) -
Pink cubic halite (NaCl; halide class) crystals on a nahcolite matrix (NaHCO3; a carbonate, and mineral form of sodium bicarbonate, used as baking soda). (from Mineral) -
Schist is a metamorphic rock characterized by an abundance of platy minerals. In this example, the rock has prominent sillimanite porphyroblasts as large as 3 cm (1.2 in). (from Mineral) -
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Muscovite, a mineral species in the mica group, within the phyllosilicate subclass (from Mineral) -
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Black andradite, an end-member of the orthosilicate garnet group. (from Mineral) -
Epidote often has a distinctive pistachio-green colour. (from Mineral) -
Diamond is the hardest natural material, and has a Mohs hardness of 10. (from Mineral) -
Perfect basal cleavage as seen in biotite (black), and good cleavage seen in the matrix (pink orthoclase). (from Mineral) -
Mohs Scale versus Absolute Hardness (from Mineral) -
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When minerals react, the products will sometimes assume the shape of the reagent; the product mineral is termed a pseudomorph of (or after) the reagent. Illustrated here is a pseudomorph of kaolinite after orthoclase. Here, the pseudomorph preserved the Carlsbad twinning common in orthoclase. (from Mineral)
Did you know ...?
- ... that the mineral shigaite (hexagonal crystal pictured) is named for the Japanese Prefecture where it was discovered in 1985?
- ... that naturally-occurring quasicrystals can be found in the rare minerals khatyrkite and cupalite?
- ... that the existence of the mineral frankdicksonite was predicted before its discovery?
- ... that seifertite, one of the densest polymorphs of silica, is named after Friedrich Seifert and has only been found in meteorites?
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| Common minerals | ||
Gemmological classifications by E. Ya. Kievlenko (1980), updated | |||||||||
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