Tetragonal minerals

Cahnite (Cahnit in German, Cahnita in Spanish, Канит in Russian) is a brittle white or colorless mineral that has perfect cleavage and is usually transparent. It usually forms tetragonal-shaped crystals and it has a hardness of 3 mohs. Cahnite was discovered in the year 1921. It was named Cahnite to honor Lazard Cahn (1865–1940), who was a mineral collector and dealer. It is usually found in the Franklin Mine, in Franklin, New Jersey, but has also been found in Japan as well as in the Vallerano quarries in Rome, Italy. The geological environment that it occurs in is in pegmatites cutting a cha

Imogolite is an aluminium silicate clay mineral with the chemical formula . It occurs in soils formed from volcanic ash and was first described in 1962 for an occurrence in Uemura, Kumamoto prefecture, Kyushu Region, Japan. Its name originates from the Japanese word , which refers to the brownish yellow soil derived from volcanic ash. It occurs together with allophane, quartz, cristobalite, gibbsite, vermiculite and limonite.

Sincosite is a green mineral discovered in 1922. It is named for Sincos, Daniel Alcides Carrión Province, Peru, where it was first discovered.

Weddellite (CaC2O4·2H2O) is a mineral form of calcium oxalate named for occurrences of millimeter-sized crystals found in bottom sediments of the Weddell Sea, off Antarctica. Occasionally, weddellite partially dehydrates to whewellite, forming excellent pseudomorphs of grainy whewellite after weddellite's short tetragonal dipyramids. It was first described in 1936 but only named in 1942.

Archerite (IMA symbol: Aht) is a phosphate mineral with chemical formula (K,NH4)H2PO4. It's named after Michael Archer (born 25 March 1945), professor of Biology, University of New South Wales. Its type locality is Petrogale Cave, Madura Roadhouse, Dundas Shire, Western Australia. It occurs in guano containing caves as wall encrustations and stalactites.

Manganvesuvianite is a rare mineral with formula . The mineral is red to nearly black in color. Discovered in South Africa and described in 2002, it was so named for the prevalence of manganese in its composition and its relation to vesuvianite.

Cryptomelane (K(Mn4+,Mn2+)8O16) is the potassium endmember of the hollandite group, a family of tectomanganates with a 2 × 2 tunnel structure.

Crookesite is a selenide mineral composed of copper and selenium with variable thallium and silver.

Baotite is a rare mineral with the chemical formula Ba4Ti4(Ti, Nb, Fe)4(Si4O12)O16Cl, recognized as having a unique four-fold silicate ring. Crystals are tetragonal, though commonly deformed to the extent of appearing monoclinic. Named for the locality of first discovery, Baotou, China, baotite has been found in hydrothermal veins and alkalic rocks in various locations around the world.

Cuprostibite  (the name is formed from the addition of two words: cuprum and stibium) — a very rare polymetallic mineral of the sulfide class, consisting of mixed copper and thallium stibnite (although not in all samples), sometimes with admixtures of tin and other metals, ideal formula Cu2(Sb,Tl) or Cu2Sb. The mineral is opaque, it has a metallic luster and a beautiful color from steel gray to violet-pink when freshly chipped.

Hardystonite is a rare calcium zinc silicate mineral first described from the Franklin, New Jersey, U.S. zinc deposits. It often contains lead, which was detrimental to the zinc smelting process, so it was not a useful ore mineral. Like many of the famous Franklin minerals, hardystonite responds to short wave ultraviolet (254 nm wavelength) light, emitting a fluorescence from dark purple to bright violet blue. In daylight, it is white to gray to light pink in color, sometimes with a vitreous or greasy luster. It is very rarely found as well formed crystals, and these are usually rectangul

Metazeunerite is an arsenate mineral with a chemical formula of Cu(UO2)2(AsO4)2·8H2O. The origin of this mineral is almost always from the natural dehydration process of zeunerite.

Cumengeite, also known as cumengite, is a secondary mineral that was named after mining engineer Bernard Louis Philippe Édouard Cumenge, who found the first specimens. It is easily confused with diaboleite. It is a valid species that was first described prior to 1959, and is grandfathered now, but it has been a valid species since 1893, since pre-IMA. It is the hydroxychloride of lead and copper.

Wardite is a hydrous sodium aluminium phosphate hydroxide mineral with formula: NaAl3(PO4)2(OH)4·2(H2O). Wardite is of interest for its rare crystallography. It crystallizes in the tetragonal trapezohedral class and is one of only a few minerals in that class. Wardite forms vitreous green to bluish green to white to colorless crystals, with pyramidal {102} or {114} faces and with {001} usually present masses. Also appears as fibrous encrustations. It has a Mohs hardness of 5 and a specific gravity of 2.81–2.87.

Tapiolite [(Fe, Mn)(Nb, Ta)2O6] is a black mineral series that is an ore of niobium and tantalum. The tapiolite group includes tapiolite-(Fe) or ferrotapiolite and tapiolite-(Mn) or manganotapiolite. Tapiolite-(Fe) is by far the more common of the two.

Béhierite is a very rare borate mineral, and the tantalum endmember of a solid solution series formed with schiavinatoite, its niobium analogue.

Piypite is a rare potassium, copper sulfate mineral with formula: K2Cu2O(SO4)2. It crystallizes in the tetragonal system and occurs as needlelike crystals and masses. Individual crystals are square in cross-section and often hollow. It is emerald green to black in color with a vitreous to greasy luster.

Bukovite is a rare selenide mineral with formula Tl2Cu3FeSe4. It is a brown to black metallic mineral which crystallizes in the tetragonal system.

Effenbergerite is the natural occurrence of the color Han blue. It was first found in the Wessels mine, Kalahari Manganese Field, South Africa.

Chernovite-(Y) is a mineral. It was first described in 1967 as Chernovite, named after the Russian geologist Aleksandr A. Chernov. The suffix -(Y) was added in 1987. It is a colourless to pale yellow mineral with a vitreous luster. It has a tetragonal crystalline structure, and has the chemical makeup of Y(AsO4), which is yttrium, arsenic, and oxygen, at a 1:1:4 ratio. It has a specific gravity of 4.866g/cm3.

Fluorapophyllite-(K), formerly known as apophyllite-(KF) and sometimes simply referred to as fluorapophyllite, is the most common mineral of the apophyllite group, with the chemical formula of KCa4Si8O20(F,OH)·8(H2O). It gets the first part of its name, "fluor", because it contains more fluorine than hydroxide compared to the other minerals in the apophyllite group.

Steacyite is a complex silicate mineral containing thorium and uranium; formula . It forms small brown or yellow green crystals, often cruciform twinned crystals. It is radioactive. It was discovered at Mont-Saint-Hilaire, Quebec in 1982 and is named after Harold Robert Steacy (1923–2012), mineralogist.

Routhierite is a rare thallium sulfosalt mineral with formula .

Zavaritskite is a rare mineral of the halide class, bismuth oxyhalide with the chemical formula (BiO)F. It is named after the Soviet geologist and petrographer, academician of the USSR Academy of Sciences Alexander Nikolaevich Zavaritsky. It was discovered in 1962 by Soviet scientists. Zavaritskite is part of matlockite group of minerals.

Pinnoite is a magnesium borate mineral with formula: MgB2O(OH)6 or MgB2O4·3(H2O). It crystallizes in the tetragonal crystal system and occurs as colorless to yellow or light green radial fibrous clusters and rarely as short prismatic crystals.

Gugiaite is a melilite mineral, named for the Chinese village of Gugia where it was first discovered. Its chemical formula is . It occurs mostly in skarns with melanite adjacent to an alkali syenite and has no economic value. Its crystals are small tetragonal tablets with vitreous luster and perfect cleavage. It is colorless and transparent with a density of three. The mineral belongs to space group P21m and is strongly piezoelectric.

Narsarsukite is a rare silicate mineral with either the chemical formula or .

Khatyrkite ( ) is a rare mineral which is mostly composed of copper and aluminium, but may contain up to about 15% of zinc or iron. Its chemical structure is described by an approximate formula or . It was discovered in 1985 in a placer in association with another rare mineral cupalite (). These two minerals have only been found at in the area of the Iomrautvaam, a tributary of the Khatyrka river, in the Koryak Mountains, in Anadyrsky District (former Beringovsky District), Chukotka, Russia. Analysis of one of the samples containing khatyrkite showed that the small rock was from a meteorite. A

Mooihoekite is a copper iron sulfide mineral with chemical formula of Cu9Fe9S16. The mineral was discovered in 1972 and received its name from its discovery area, the Mooihoek mine in Transvaal, South Africa.

Aminoffite is a mineral of the silicate class. It was first described in 1937 and received its name to honor the Swedish mineralogist and artist Gregori Aminoff (1883–1947), who was an expert in the mineralogy of Långban and worked at the Swedish Museum of Natural History.

Eskebornite is a selenide mineral with the formula CuFeSe2. It crystallizes in the tetragonal system and it has a brassy colour. Eskebornite is sometimes found as thick tabular crystals, but is more often found intergrown with other selenides. It is part of the chalcopyrite group and forms a series with chalcopyrite.

Coccinite is a rare mercury iodide mineral with chemical formula of HgI2, mercury(II) iodide. It was first discovered in Casas Viejas, Mexico; it has also been reported from Broken Hill, New South Wales, and from a uranium mine in Thuringia and old mercury workings in the Rhineland-Palatinate in Germany. At the Thuringia deposit the mineral occurs as a sublimation product resulting from fires associated with pyrite-bearing graptolitic slate.

Rosenbergite is a mineral with the chemical formula AlF3·3H2O. It is a trihydrate of aluminium fluoride.

Tripuhyite is an iron antimonate mineral with composition FeSbO4.

thumb | right Daubréeite is a rare bismuth oxohalide mineral with formula . It is a creamy-white to yellow-brown, soft, earthy clay–like mineral which crystallizes in the tetragonal crystal system. It is a member of the matlockite group.

Chatkalite is a copper, iron, tin sulfide mineral with formula Cu6Fe2+Sn2S8. It crystallizes in the tetragonal crystal system and forms as rounded disseminations within tetrahedrite in quartz veins.

Uramphite is a rarely-found phosphate mineral in the "phosphate, arsenate and vanadate" mineral class with chemical composition (NH4)2[UO2PO4]2·6H2O from which it is seen to be a hydrated ammonium uranyl phosphate.

Hiärneite is an oxide mineral named after the Swedish geologist Urban Hiärne (1641–1727). The mineral can be found in rocks that mainly consists of fine grained phlogopite. Hiärneite is the first known mineral that contains both of the chemical elements antimony and zirconium. The mineral was described in 1997 for its occurrence in a skarn environment in Långban iron–manganese deposit of the Filipstad district, Värmland, Sweden.

Ashburtonite is a rare lead copper silicate-bicarbonate mineral with formula: HPb4Cu2+4Si4O12(HCO3)4(OH)4Cl.

alloy mineral

thumb|right|Lipscombite: Small yellowish-green crystals, Lichtenberg Absetzer Mine dump, Ronneburg Uranium deposit, Gera, Thuringia, Germany thumb|right|Lipscombite: Small black crystals on dark background. Smithsonian National Museum of Natural History

Zinclipscombite is a dark-green to brown zinc iron phosphate mineral with the formula Zn(Fe3+)2(PO4)2(OH)2. It occurs as fibrous spheres and exhibits tetragonal crystal structure.

Wakefieldite () is an uncommon rare-earth element vanadate mineral. There are four main types described of wakefieldite- wakefieldite-(La), wakefieldite-(Ce), wakefieldite-(Nd), and wakefieldite-(Y), depending upon the dominant rare-earth metal ion present. Wakefieldite has a Mohs hardness ranging from 4 to 5. Wakefieldite forms crystals of tetragonal structure. In terms of crystal structure, it is the vanadate analog of the rare-earth phosphate mineral xenotime. Unlike xenotime, it is more favorable for wakefieldite to contain the lighter rare-earth elements over the heavier ones. Due to the

Wakefieldite-(Ce) () is the cerium analogue of the uncommon rare-earth element vanadate mineral Wakefieldite. It is a member of the xenotime group.

Ordoñezite or ordóñezite is a rare tetragonal zinc antimonate mineral with chemical formula: ZnSb2O6.

Mathesiusite is a sulfate mineral containing potassium, vanadium, and uranium and has the chemical formula: K5(UO2)4(SO4)4(VO5)·4(H2O). It is a secondary mineral formed during post-mining processes.

Sweetite has a general formula of Zn(OH)2. The name is given after a curator of mineral department of the British Museum, Jessie May Sweet (1901–1979). It occurs in an oxidized vein in limestone bedrock with galena, ashoverite, wülfingite, anglesite, cerussite, hydrocerussite, litharge, fluorite, palygorskite and calcite.

Xiangjiangite is a phosphate mineral discovered near and named for the Xiang Jiang River in China. It was approved by the IMA in 1978, and was named after its locality.

Reidite is a rare polymorph of ZrSiO4 created when zircon experiences high pressure and temperature. Reidite is denser than zircon and has the same crystal structure as scheelite. All natural occurrences of reidite are associated with meteorite impact events.

Ashoverite is one of three polymorphs of zinc hydroxide, Zn(OH)2. It is a rare mineral first found in a limestone quarry near Ashover, Derbyshire, England, in 1988. It has also been found in the Harz mountain range in Germany, and in Namibia.

Zhangpeishanite is a mineral named after Zhang Peishan (Chinese: 张培善), a Chinese mineralogist at the Institute of Geology of the Chinese Academy of Sciences, in recognition of his contributions to studying the mineralogy Bayan Obo deposit, where the mineral is mined. The Bayan Obo deposit is also known for being a world class deposit. The mineral got approved by the IMA in 2006 but was published two years after its approval. The mineral consists of barium chloride fluoride.

Xenotime-(Gd) is the gadolinium endpoint of Xenotime with the ideal formula . It is one of the few known gadolinium-dominant rare earth minerals.

Mawsonite is a brownish orange sulfosalt mineral, containing copper, iron, tin, and sulfur: Cu6Fe2SnS8.

Ewingite is a complex hydrous uranyl carbonate mineral of magnesium and calcium. Its chemical formula is . It was discovered by Jakub Plášil of the Institute of Physics at the Academy of Sciences of the Czech Republic in the Plavno mine, Czech Republic. Travis Olds of the University of Notre Dame and colleagues described ewingite, which is the most structurally complex known mineral on Earth. Ewingite is named in honor of Rodney C. Ewing, Professor of Geological Sciences at Stanford University, USA.

Schiavinatoite is a very rare borate mineral, and the niobium endmember of a solid solution formed with béhierite.