Sapphire is a preciousgemstone, a variety of the mineralcorundum, consisting ofaluminium oxide (α-Al₂O₃) with trace amounts of elements such asiron,titanium,cobalt,lead,chromium,vanadium,magnesium,boron, andsilicon. The namesapphire is derived from the Latin wordsapphirus, itself from theGreek wordsappheiros (σάπφειρος, itself from a Semitic origin), which referred tolapis lazuli. Sapphire with colors other than its typical blue is referred to as "fancy sapphire", and can be in yellow, purple, orange, and green colors; "parti sapphires" show two or more colors. Red corundum stones also occur, but are calledrubies 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 injewelry. They also may be created synthetically in laboratories for industrial or decorative purposes in largecrystal boules. It occurs in association withruby,zircon,biotite,muscovite,calcite,dravite andquartz.

Sapphire has a remarkablehardness, with a score of 9 on theMohs scale, the third-hardest mineral afterdiamond at 10 andmoissanite at 9.5. Non-ornamental applications includeinfraredoptical components, high-durabilitywindows,wristwatch crystals and movement bearings, and very thinelectronic wafers, which are used as theinsulatingsubstrates of special-purposesolid-state electronics such as integrated circuits andGaN-based blueLEDs. (Full article...)

Beryl (/ˈbɛrəl/BERR-əl) is amineral composed ofberylliumaluminiumsilicate with thechemical formula Be₃Al₂(SiO₃)₆. Well-known varieties of beryl includeemerald andaquamarine. Naturally occurringhexagonalcrystals of beryl can be up to several meters in size, butterminated crystals are relatively rare. Pure beryl is colorless, but it is frequently tinted by impurities; possible colors are green, blue, yellow, pink, and red (the rarest). It is an ore source ofberyllium. (Full article...)

Micas (/ˈmaɪkəz/MY-kəz) are a group ofsilicateminerals whose outstanding physical characteristic is that individual micacrystals can easily be split into fragile elastic plates. This characteristic is described asperfectbasal cleavage. Mica is common inigneous andmetamorphic rock and is occasionally found as small flakes insedimentary rock. It is particularly prominent in manygranites,pegmatites, andschists, and "books" (large individual crystals) of mica several feet across have been found in some pegmatites.

Micas are used in products such asdrywalls,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...)

Cinnabar (/ˈsɪnəˌbɑːr/; from Ancient Greek κιννάβαρι (kinnábari)), also calledcinnabarite (/ˌsɪnəˈbɑːraɪt/) ormercurblende, is the brightscarlet to brick-red form ofmercury(II) sulfide (HgS). It is the most common sourceore for refiningelemental mercury and is the historic source for the brilliant red or scarlet pigment termedvermilion and associated red mercury pigments.

Cinnabar generally occurs as a vein-fillingmineral associated withvolcanic activity andalkalinehot springs. The mineral resemblesquartz in symmetry and it exhibitsbirefringence. Cinnabar has a meanrefractive index near 3.2, ahardness between 2.0 and 2.5, and aspecific gravity of approximately 8.1. The color and properties derive from a structure that is a hexagonal crystallinelattice belonging to thetrigonal crystal system, crystals that sometimes exhibittwinning.

Cinnabar has been used for its color since antiquity in theNear East, including as arouge-typecosmetic, in theNew World since theOlmec culture, and inChina since as early as theYangshao culture, where it was used in coloringstoneware. 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 thetoxicity of the mercury component, which was recognized as early asancient Rome. (Full article...)

Opal is ahydratedamorphous form ofsilica (SiO₂·nH₂O); itswater 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 amineraloid, unlikecrystalline forms of silica, which are consideredminerals. It is deposited at a relatively low temperature and may occur in thefissures of almost any kind ofrock, being most commonly found withlimonite,sandstone,rhyolite,marl, andbasalt.

The nameopal is believed to be derived from theSanskrit wordupala (उपल), which means 'jewel', and later the Greek derivativeopállios (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 todiffract 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...)

Crystallography is the branch of science devoted to the study of molecular andcrystalline structure and properties. The wordcrystallography is derived from theAncient Greek wordκρύσταλλος (krústallos; "clear ice, rock-crystal"), andγράφειν (gráphein; "to write"). In July 2012, theUnited 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 asX-ray crystallography, are themselves important scientific topics. Crystallography ranges from the fundamentals ofcrystal structure to the mathematics ofcrystal geometry, including those that arenot periodic orquasicrystals. At the atomic scale it can involve the use ofX-ray diffraction to produce experimental data that the tools ofX-ray crystallography can convert into detailed positions of atoms, and sometimes electron density. At larger scales it includes experimental tools such asorientational imaging to examine the relative orientations at thegrain boundary in materials. Crystallography plays a key role in many areas of biology, chemistry, and physics, as well as in emerging developments in these fields. (Full article...)

Talc, ortalcum, is aclay mineralcomposed ofhydratedmagnesiumsilicate, with thechemical formulaMg₃Si₄O₁₀(OH)₂. Talc in powdered form, often combined withcorn starch, is used asbaby powder. This mineral is used as athickening agent andlubricant. It is an ingredient inceramics,paints, androofing material. It is a main ingredient in manycosmetics. It occurs asfoliated tofibrous masses, and in an exceptionally rarecrystal form. It has a perfectbasal cleavage and an uneven flat fracture, and it is foliated with a two-dimensionalplaty form.

TheMohs scale of mineral hardness, based onscratchhardness comparison, defines value 1 as the hardness of talc, the softest mineral. When scraped on astreak 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 pearlyluster. Talc is not soluble in water, and is slightly soluble in dilutemineral acids.

Soapstone is ametamorphic rock composed predominantly of talc. (Full article...)

Hematite (/ˈhiːməˌtaɪt,ˈhɛmə-/),also spelled ashaematite, is a commoniron oxide compound with the formulaFe₂O₃ and is widely found inrocks andsoils. Hematite crystals belong to therhombohedral lattice system which is designated thealpha polymorph ofFe
₂O
₃. It has the samecrystal structure ascorundum (Al
₂O
₃) andilmenite (FeTiO
₃). With this crystal structure geometry it forms a completesolid 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 ismined as an importantore mineral of iron. It is electrically conductive. Hematite varieties includekidney ore,martite (pseudomorphs aftermagnetite),iron rose andspecularite (specular hematite). While these forms vary, they all have a rust-redstreak. Hematite is not onlyharder than pure iron, but also much morebrittle. The termkidney ore may be broadly used to describebotryoidal, mammillary, or reniform hematite.Maghemite is a polymorph of hematite (γ-Fe
₂O
₃) with the same chemical formula, but with aspinel structure like magnetite.

Large deposits of hematite are found inbanded iron formations. Gray hematite is typically found in places that have still, standing water, or mineralhot springs, such as those inYellowstone National Park inNorth America. The mineral mayprecipitate 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 ofvolcanic activity.

Clay-sized hematite crystals also may occur as a secondary mineral formed byweathering processes insoil, and along with other iron oxides oroxyhydroxides such asgoethite, which is responsible for the red color of manytropical, ancient, or otherwise highly weathered soils. (Full article...)

Kaolinite (/ˈkeɪ.ələˌnaɪt,-lɪ-/KAY-ə-lə-nyte, -⁠lih-; also calledkaolin) is aclay mineral, with the chemical compositionAl₂Si₂O₅(OH)₄. It is a layeredsilicate mineral, with one "tetrahedral" sheet ofsilicatetetrahedra (SiO₄) linked to one "octahedral" sheet ofaluminateoctahedrons (AlO₂(OH)₄) throughoxygenatoms on one side, and another such sheet throughhydrogen bonds on the other side.

Kaolinite is a soft, earthy, usually white, mineral (dioctahedral phyllosilicateclay), produced by the chemical weathering ofaluminium silicate minerals likefeldspar. It has a lowshrink–swell capacity and a lowcation-exchange capacity (1–15 meq/100 g).

Rocks that are rich in kaolinite, andhalloysite, are known askaolin (/ˈkeɪ.əlɪn/) orchina clay. In many parts of the world kaolin is colored pink-orange-red byiron oxide, giving it a distinctrust 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 atProvidence Canyon State Park in Georgia, United States.

Kaolin is an importantraw material in many industries and applications. Commercial grades of kaolin are supplied and transported as powder, lumps, semi-dried noodle orslurry. 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...)

Ruby is apinkish-red to blood-redgemstone, a variety of themineralcorundum (aluminium oxide). Ruby is one of the most popular traditional jewelry gems and is very durable. Other varieties of gem-quality corundum are calledsapphires, and rubies are also sometimes referred to as "red sapphires".

Ruby is one of the traditionalcardinal gems, alongsideamethyst,sapphire,emerald, anddiamond. The wordruby comes fromruber,Latin for red. The color of a ruby is due to the presence ofchromium.

Some gemstones that are popularly or historically called rubies, such as theBlack Prince's Ruby in the BritishImperial State Crown, are actuallyspinels. These were once known as "Balas rubies".

The quality of a ruby is determined by its color, cut, and clarity, which, along withcarat 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-likerutileinclusions may indicate that the stone has been treated. Ruby is the traditionalbirthstone for July and is usually pinker thangarnet, although somerhodolite garnets have a similar pinkish hue to most rubies. The world's most valuable ruby to be sold at auction is theEstrela de Fura, which sold for US$34.8 million. (Full article...)

Halite (/ˈhælaɪt,ˈheɪlaɪt/HAL-yte,HAY-lyte), commonly known asrock salt, is a type ofsalt, themineral (natural) form ofsodium chloride (NaCl). Halite formsisometric 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 otherevaporite deposit minerals such as several of thesulfates,halides, andborates. The namehalite is derived from the Ancient Greek word for "salt",ἅλς (háls). (Full article...)

Zircon (/ˈzɜːrkɒn,-kən/) is amineral belonging to the group ofnesosilicates and is a source of the metalzirconium. Its chemical name iszirconium(IV) silicate, and its corresponding chemical formula isZrSiO₄. Anempirical formula showing some of the range of substitution in zircon is (Zr_1–y,REE_y)(SiO₄)_1–x(OH)_4x–y. Zircon precipitates fromsilicatemelts and has relatively high concentrations ofhigh field strength incompatible elements. For example,hafnium is almost always present in quantities ranging from 1 to 4%. Thecrystal structure of zircon istetragonalcrystal system. The natural color of zircon varies between colorless, yellow-golden, red, brown, blue, and green.

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

Incrystallography, thecubic (orisometric)crystal system is acrystal system where theunit cell is in the shape of acube. This is one of the most common and simplest shapes found incrystals andminerals.

There are three main varieties of these crystals:

• Primitive cubic (abbreviatedcP and alternatively calledsimple cubic)
• Body-centered cubic (abbreviatedcI orbcc)
• Face-centered cubic (abbreviatedcF orfcc)

Note: the termfcc is often used synonymously for thecubic close-packed orccp 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 arefcc but not close-packed.
Each is subdivided into other variants listed below. Although theunit cells in these crystals are conventionally taken to be cubes, theprimitive unit cells often are not. (Full article...)

Chalk is a soft, white,porous,sedimentarycarbonate rock. It is a form oflimestone composed of the mineralcalcite and originally formed under the sea by the accumulation andlithification of hard parts of organisms, mostly microscopicplankton, which had settled to thesea floor. Chalk is common throughoutWestern Europe, where deposits underlie parts ofFrance, and steep cliffs are often seen where they meet the sea in places such as theDover cliffs on theKent coast of theEnglish Channel.

Chalk is mined for use in industry, such as forquicklime,bricks and builder'sputty, and inagriculture, for raisingpH in soils with highacidity. 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, orgypsum. (Full article...)

Tourmaline (/ˈtʊərməlɪn,-ˌliːn/ ^ⓘTOOR-mə-lin, -⁠leen) is acrystallinesilicatemineral group in whichboron iscompounded withelements such asaluminium,iron,magnesium,sodium,lithium, orpotassium. Thisgemstone comes in a wide variety of colors.

The name is derived from theSinhalesetōramalli (ටෝරමල්ලි), which refers to thecarnelian gemstones. (Full article...)

Galena, also calledlead glance, is the natural mineral form oflead(II) sulfide (PbS). It is the most importantore oflead and an important source ofsilver.

Galena is one of the most abundant and widely distributedsulfide minerals. It crystallizes in thecubiccrystal system often showingoctahedral forms. It is often associated with the mineralssphalerite,calcite andfluorite.

As a pure specimen held in the hand, understandard 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...)

Apatite is a group ofphosphate minerals, usuallyhydroxyapatite,fluorapatite and chlorapatite, with high concentrations ofOH⁻,F⁻ andCl⁻ion, respectively, in thecrystal. The formula of the admixture of the three most commonendmembers is written asCa₁₀(PO₄)₆(OH,F,Cl)₂, and the crystal unit cell formulae of the individualminerals are written as Ca₁₀(PO₄)₆(OH)₂, Ca₁₀(PO₄)₆F₂ and Ca₁₀(PO₄)₆Cl₂.

The mineral was named apatite by the GermangeologistAbraham Gottlob Werner in 1786, although the specific mineral he had described was reclassified as fluorapatite in 1860 by the GermanmineralogistKarl 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 meansto deceive.

As hydroxyapatite, it forms a major part of theteeth andbones of vertebrate animals. (Full article...)

Incrystallography, acrystal system is a set ofpoint groups (a group of geometric symmetries with at least one fixed point). Alattice system is a set ofBravais 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 acrystal family.

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

Zeolites are a group of severalmicroporous, crystallinealuminosilicate minerals commonly used as commercialadsorbents andcatalysts. They mainly consist ofsilicon,aluminium, andoxygen, and have the general formulaMⁿ⁺
_1/n(AlO
₂)⁻
(SiO
₂)
_x･yH
₂O whereMⁿ⁺
_1/n is either a metal ion or H⁺.

The term was originally coined in 1756 bySwedishmineralogistAxel Fredrik Cronstedt, who observed that rapidly heating a material, believed to have beenstilbite, produced large amounts of steam from water that had beenadsorbed by the material. Based on this, he called the materialzeolite, from theGreekζέω (zéō), meaning "to boil" andλίθος (líthos), meaning "stone". (Full article...)

Diamond is asolid form of the element carbon with its atoms arranged in acrystal structure calleddiamond cubic. Diamond is tasteless, odorless, strong, brittle solid, colorless in pure form, a poor conductor of electricity, and insoluble in water. Another solid form of carbon known asgraphite is thechemically stable form of carbon atroom temperature and pressure, but diamond ismetastable and converts to it at a negligible rate under those conditions. Diamond has the highesthardness andthermal conductivity of any natural material, properties that are used in major industrial applications such as cutting and polishing tools.

Because the arrangement of atoms in diamond is extremely rigid, few types of impurity can contaminate it (two exceptions areboron andnitrogen). Small numbers ofdefects 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 highrefractive index and a relatively highoptical 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'smantle, 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 involcanic eruptions and deposited inigneous rocks known askimberlites andlamproites.

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

Chalcopyrite (/ˌkælkəˈpaɪˌraɪt,-koʊ-/KAL-kə-PY-ryte, -⁠koh-) is acopperironsulfide mineral and the most abundantcopper ore mineral. It has thechemical formula CuFeS₂ and crystallizes in thetetragonal system. It has abrassy to golden yellow color and ahardness of 3.5 to 4 on theMohs scale. Itsstreak 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 sulfidesbornite (Cu₅FeS₄),chalcocite (Cu₂S),covellite (CuS),digenite (Cu₉S₅); carbonates such asmalachite andazurite, and rarely oxides such ascuprite (Cu₂O). It is rarely found in association withnative copper. Chalcopyrite is a conductor of electricity.

Copper can be extracted from chalcopyrite ore using various methods. The two predominant methods arepyrometallurgy andhydrometallurgy, the former being the most commercially viable. (Full article...)

Rutile is anoxide mineral composed oftitanium dioxide (TiO₂), the most common natural form of TiO₂. Rarerpolymorphs of TiO₂ are known, includinganatase,akaogiite, andbrookite.

Rutile has one of the highestrefractive indices atvisible wavelengths of any known crystal and also exhibits a particularly largebirefringence and highdispersion. Owing to these properties, it is useful for the manufacture of certain optical elements, especiallypolarization optics, for longervisible andinfrared wavelengths up to about 4.5 micrometres. Natural rutile may contain up to 10%iron and significant amounts ofniobium andtantalum.

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

Asbestos (/æsˈbɛstəs,æz-,-tɒs/ass-BES-təs, az-, -⁠toss) is a group of naturally occurring, fibroussilicate minerals, used for thousands of years to create flexible objects that resist fire, such as fireproof fabrics, but now known to betoxic andcarcinogenic.

There are six types, all of which are composed of long and thin fibrouscrystals, each fibre (particulate with length substantially greater than width) being composed of many microscopic "fibrils" that can be released into the atmosphere byabrasion and other processes. Inhalation of asbestos fibres can lead to various dangerouslung conditions, includingmesothelioma,asbestosis, andlung cancer. As a result of these health effects, asbestos is considered a serioushealth andsafety hazard.

Archaeological studies have found evidence of asbestos being used as far back as theStone Age to strengthenceramic 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 excellentthermal andelectrical 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), untilits 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 andfireproofing 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 areasbestosis (scarring of the lungs due to asbestos inhalation) andmesothelioma (a type of cancer). (Full article...)

Graphite (/ˈɡræfaɪt/) is acrystalline allotrope (form) of the elementcarbon. It consists of many stackedlayers ofgraphene, typically in excess of hundreds of layers. Graphite occurs naturally and is the most stable form of carbon understandard 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 includingrefractories (50%),lithium-ion batteries (18%),foundries (10%), andlubricants (5%), among others (17%). Graphite converts todiamond under extremely high pressure and temperature. Graphite's low cost, thermal and chemical inertness and characteristic conductivity of heat and electricity finds numerous applications in high energy and high temperature processes. (Full article...)

Andesite (/ˈændəzaɪt/) is avolcanic rock ofintermediate composition. In a general sense, it is the intermediate type betweensilica-poorbasalt and silica-richrhyolite. It is fine-grained (aphanitic) toporphyritic in texture, and is composed predominantly of sodium-richplagioclase pluspyroxene orhornblende.

Andesite is the extrusive equivalent ofplutonicdiorite. Characteristic ofsubduction zones, andesite represents the dominant rock type inisland arcs. The average composition of thecontinental crust is andesitic. Along with basalts, andesites are a component of theMartian crust.

The nameandesite is derived from theAndes mountain range, where this rock type is found in abundance. It was first applied byChristian Leopold von Buch in 1826. (Full article...)

Julian Royce Goldsmith (1918–1999) was amineralogist andgeochemist at theUniversity of Chicago (Moore, 1971). Goldsmith, along with colleagueFritz Laves, first defined the crystallographic polymorphism ofalkali feldspar (Newton, 1989). Goldsmith also experimented on the temperature dependence of the solid solution betweencalcite anddolomite (Newton, 1989). Goldsmith's research also led him to experiment with the determination of the stability of intermediate structural states ofalbite (Newton, 1989). For his outstanding contributions to the study of mineralogy and geochemistry, Goldsmith was awarded the prestigiousRoebling Medal by theMineralogical Society of America in 1988 (Newton, 1989). The mineraljulgoldite was named for him. (Full article...)

George Shirley Switzer (June 11, 1915 – March 23, 2008) was an Americanmineralogist who is credited with starting theSmithsonian Institution's famedNational Gem and Mineral Collection by acquiring theHope Diamond for the museum in 1958. Switzer made the arrangements when renownedNew York CityjewelerHarry Winston decided to donate the Hope Diamond to the Smithsonian.

Switzer was also known for his analysis ofMoon rocks which were brought back byNASAmissions to theMoon. (Full article...)

Konrad Oebbeke (2 November 1853,Hildesheim – 1 February 1932) was a Germangeologist andmineralogist.

He studied at the Universities ofHeidelberg andErlangen, obtaining his doctorate at theUniversity of Würzburg in 1877. Afterwards he worked as an assistant to the Geological Survey of Bavaria. He served asprivat-docent at theUniversity of Munich, later becoming a professor of mineralogy and geology atErlangen (1887).
From 1895 to 1927 he was a professor at theTechnische Hochschule ofMunich. (Full article...)

Jean-André Mongez (21 November 1750 – May 1788) was a Frenchpriest andmineralogist. He is presumed to have died atVanikoro, on theLa Pérouse expedition. (Full article...)

Paul Heinrich Ritter von Groth (23 June 1843 – 2 December 1927) was a Germanmineralogist. His most important contribution to science was his systematic classification of minerals based on their chemical compositions and crystal structures. (Full article...)

Carl Franz Anton Ritter von Schreibers (15 August 1775 – 21 May 1852) was an Austriannaturalist who was involved in organizing the natural history cabinet "Naturalienkabinette" of the Austrian emperor Franz II which later became the natural history museum of Vienna. He took an interest in zoology as well as minerals and particularly meteorites. (Full article...)

Harold "Hal" Robert Steacy (June 7, 1923 – April 7, 2012) was a Canadianmineralogist who was thecurator of theCanadian National Mineral Collection at theGeological Survey of Canada inOttawa. The mineralsteacyite is named for him. (Full article...)

Enrico Clerici (15 October 1862 – 26 August 1938) was an Italianmineralogist andgeologist. From 1903 on, he worked at theUniversity of Rome. He published in 1907 the composition of a solution with a density of 4.25 g/cm³ at 20°C, to determine the density of minerals. TheClerici solution is a mixture ofthalliumformate (Tl(CHO₂)) and thalliummalonate (Tl(C₃H₃O₄)) in water. (Full article...)

Jacques-Louis, Comte de BournonFRS,FGS (21 January 1751 – 24 August 1825) was aFrenchsoldier andmineralogist who came toEngland after theFrench Revolution. He gained prominence in the scientific community, being elected a fellow of theRoyal Society and was a founding member of theGeological Society before returning to France after theBourbon Restoration. (Full article...)

Leopold Heinrich Fischer (19 December 1817,Fribourg-en-Brisgau – 2 February 1886, Fribourg-en-Brisgau) was a Germanzoologist andmineralogist. (Full article...)

George Thurland PriorFRS (16 December 1862 – 8 March 1936) was a Britishmineralogist. He made great contributions to mineralogical chemistry,petrology andmeteoritics.

He was born inOxford, England, and attendedMagdalen College there in 1881. He received a first class in the Honour School inChemistry in 1885 andPhysics in 1886. Later he went to study inGermany. He obtained his Doctor of Science degree fromOxford University in 1905. (Full article...)

Joan Abella i Creus (Sabadell,Barcelona, 1968) is a Catalangemmologist andmineralogist who discoveredabellaite, amineral that receives this name in his honor. (Full article...)

Oskar Lenz (13 April 1848 inLeipzig – 1 March 1925 inSooß) was a German-Austriangeologist andmineralogist born inLeipzig. (Full article...)

Walter Frederick Ferrier (1865–1950) was aCanadiangeologist andmining engineer.

He graduated fromMcGill University's school of mining engineering. He was a tirelessmineral collector and was known for walking straight into mining offices to request specimens. Consequently, he created large collections of mineral specimens of a quality still admired to this day. Many classic specimens would never be in collections had it not been for his effort and skill.
The mineral specimens he amassed were instrumental in creating the mineral collections of theSmithsonian in Washington DC, theRoyal Ontario Museum inToronto, Ontario, Canada,University of Alberta, and the museum particularly dear to his heart, theRedpath Museum at McGill University inMontreal, Quebec, Canada. (Full article...)

Su Song (Chinese:蘇頌;Pe̍h-ōe-jī:So͘ Siōng, 1020–1101),courtesy nameZirong (Chinese:子容;Pe̍h-ōe-jī:Chú-iông), was a Chinesepolymathic scientist and statesman who lived during theSong dynasty (960–1279). He excelled in numerous fields including but not limited tomathematics,astronomy,cartography,geography,metallurgy,mechanical engineering,hydraulic engineering,poetry, andstatesmanship.

Su Song was the engineer for ahydro-mechanicalastronomicalclock tower located inKaifeng. It employed an earlyescapement mechanism. The escapement mechanism of Su's clock tower was invented by the Tang dynastyBuddhistmonkYi Xing and government official Liang Lingzan in 725 AD to operate a water-poweredarmillary sphere, however Su's armillary sphere was the first to utilize a mechanical clock drive. Su's clock tower also featured the oldest known endless power-transmittingchain drive, called thetian ti (天梯), or "celestial ladder", as depicted in his horological treatise. The clock tower had 133 differentclock jacks to indicate andsound the hours. The clock was dismantled by theinvadingJurchen army in 1127 AD, and although attempts were made to reassemble it, the tower was never successfully reinstated. (Full article...)

Franz Eugen Geinitz (15 February 1854,Dresden – 9 March 1925,Rostock) was a Germangeologist andmineralogist best known for his geological studies of theMecklenburg region. He was the son of geologistHanns Bruno Geinitz. (Full article...)

John WalkerFRSE (1731–1803) was a Scottish minister and natural historian. He was Regius professor ofnatural history at theUniversity of Edinburgh from 1779 to 1803. He was joint founder of theRoyal Society of Edinburgh in 1783 andmoderator of the General Assembly of the Church of Scotland in 1790. (Full article...)

Stanley Robert Mitchell (12 February 1881 – 22 March 1963) was an Australian commercialmetallurgist as well as anamateurmineralogist andethnologist. (Full article...)

Quintino Sella (Italian pronunciation:[kwinˈtinoˈsɛlla]; 7 July 1827 – 14 March 1884) was an Italianpolitician,economist and mountaineer. (Full article...)

Victor Mordechai Goldschmidt (10 February 1853 – 8 May 1933) was a Germanmineralogist,natural philosopher andart collector. He produced a nine-volume atlas of crystal forms (Atlas der Krystallformen) from 1913 to 1923 which was influential in establishing the field ofcrystallography. He introduced what are now called Goldschmidt symbols Φ and ρ (borrowed from astronomy) for the gnomonic angles of crystals. In 1933, he was dismissed from his position at theUniversity of Heidelberg due to his Jewish origins and he died shortly afterwards while in exile in Salzburg. His wife Leontine committed suicide when faced with deportation to a concentration camp. (Full article...)

Charles Thompson Prewitt (March 3, 1933 – April 28, 2022) was an American mineralogist and solid state chemist known for his work on structural chemistry of minerals andhigh-pressure chemistry. (Full article...)

François Michel de Rozière (29 September 1775,Melun – 4 November 1842, Melun) was a French mining engineer and mineralogist. (Full article...)

Ludwig Meyn (1 October 1820,Pinneberg − 4 November 1878,Uetersen), was a Germanagricultural scientist,soil scientist,geologist,journalist andmineralogist. He was the pioneer ofoil production. (Full article...)

(Karl) Heinrich/Harry (Ferdinand) Rosenbusch (24 June 1836 – 20 January 1914) was aGermanpetrographer.

Harry Rosenbusch was born inEinbeck. He taught atHeidelberg University (1877–1908), where he founded theMineralogisches-geologisches Institut. He died, aged 77, inHeidelberg. (Full article...)

André Laugier (1 August 1770, inLisieux – 19 April 1832, inParis) was a Frenchchemist,pharmacist andmineralogist. He was a cousin to famed chemistAntoine François Fourcroy and the father of astronomerPaul Auguste Ernest Laugier (1812–1872).

He received his education in his hometown ofLisieux, and during theFrench Revolution, was tasked with collecting church bells inBretagne in order for them to be melted down for the production of cannons. In 1794 he was employed as head of thegunpowder andsaltpeter works at theComite de salut public. In 1797 he received his master's degree in pharmacy, and subsequently taught classes in chemistry and pharmacy at the military training schools inToulon andLille. (Full article...)