| Rashleighite | |
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| Category | Mineral |
Rashleighite, also called henwoodite, [1] [2] is a ferrian variety of turquoise. The names are in honour of the Cornish geologists Philip Rashleigh and William Jory Henwood.
| Rashleighite | |
|---|---|
| | |
| General | |
| Category | Mineral |
Rashleighite, also called henwoodite, [1] [2] is a ferrian variety of turquoise. The names are in honour of the Cornish geologists Philip Rashleigh and William Jory Henwood.
Germanite is a rare copper iron germanium sulfide mineral, Cu26Fe4Ge4S32. It was first discovered in 1922, and named for its germanium content. It is only a minor source of this important semiconductor element, which is mainly derived from the processing of the zinc sulfide mineral sphalerite. Germanite contains gallium, zinc, molybdenum, arsenic, and vanadium as impurities.
Erythrite or red cobalt is a secondary hydrated cobalt arsenate mineral with the formula Co
3(AsO
4)
2•8H
2O. Erythrite and annabergite, chemical formula (Ni
3As
4)
2•8H
2O, or nickel arsenate form a complete series with the general formula (Co,Ni)
3(AsO
4)
2•8H
2O.
Boracite is a magnesium borate mineral with formula: Mg3B7O13Cl. It occurs as blue green, colorless, gray, yellow to white crystals in the orthorhombic - pyramidal crystal system. Boracite also shows pseudo-isometric cubical and octahedral forms. These are thought to be the result of transition from an unstable high temperature isometric form on cooling. Penetration twins are not unusual. It occurs as well formed crystals and dispersed grains often embedded within gypsum and anhydrite crystals. It has a Mohs hardness of 7 to 7.5 and a specific gravity of 2.9. Refractive index values are nα = 1.658 - 1.662, nβ = 1.662 - 1.667 and nγ = 1.668 - 1.673. It has a conchoidal fracture and does not show cleavage. It is insoluble in water (not to be confused with borax, which is soluble in water).
Alunite is a hydroxylated aluminium potassium sulfate mineral, formula KAl3(SO4)2(OH)6. It was first observed in the 15th century at Tolfa, near Rome, where it was mined for the manufacture of alum. First called aluminilite by J.C. Delamétherie in 1797, this name was contracted by François Beudant three decades later to alunite.
Powellite is a calcium molybdate mineral with formula CaMoO4. Powellite crystallizes with tetragonal - dipyramidal crystal structure as transparent adamantine blue, greenish brown, yellow to grey typically anhedral forms. It exhibits distinct cleavage and has a brittle to conchoidal fracture. It has a Mohs hardness of 3.5 to 4 and a specific gravity of 4.25. It forms a solid solution series with scheelite (calcium tungstate, CaWO4). It has refractive index values of nω=1.974 and nε=1.984.
Mindat.org is a non-commercial online database, claiming to be the largest mineral database and mineralogical reference website on the Internet. It is used by professional mineralogists, geologists, and amateur mineral collectors alike.
Grossular is a calcium-aluminium species of the garnet group of minerals. It has the chemical formula of Ca3Al2(SiO4)3 but the calcium may, in part, be replaced by ferrous iron and the aluminium by ferric iron. The name grossular is derived from the botanical name for the gooseberry, grossularia, in reference to the green garnet of this composition that is found in Siberia. Other shades include cinnamon brown (cinnamon stone variety), red, and yellow. Grossular is a gemstone.
Thorianite is a rare thorium oxide mineral, ThO2. It was originally described by Ananda Coomaraswamy in 1904 as uraninite, but recognized as a new species by Wyndham R. Dunstan. It was so named by Dunstan on account of its high percentage of thorium; it also contains the oxides of uranium, lanthanum, cerium, praseodymium and neodymium. Helium is present, and the mineral is slightly less radioactive than pitchblende, but is harder to shield due to its high energy gamma rays. It is common in the alluvial gem-gravels of Sri Lanka, where it occurs mostly as water worn, small, heavy, black, cubic crystals. The largest crystals are usually near 1.5 cm. Larger crystals, up to 6 cm (2.4 in), have been reported from Madagascar.
Scorodite is a common hydrated iron arsenate mineral, with the chemical formula FeAsO4·2H2O. It is found in hydrothermal deposits and as a secondary mineral in gossans worldwide. Scorodite weathers to limonite.
Beryllonite is a rare sodium beryllium phosphate mineral with formula NaBePO4. The tabular to prismatic monoclinic crystals vary from colorless to white or pale yellowish, and are transparent with a vitreous luster. Twinning is common and occurs in several forms. It exhibits perfect cleavage in one direction. The hardness is 5.5 to 6 and the specific gravity is 2.8. Refractive indices are nα = 1.552, nβ = 1.558 and nγ = 1.561. A few crystals have been cut and faceted, but, as the refractive index is no higher than that of quartz, they do not make very brilliant gemstones.
Botryogen is a hydrous magnesium sulfate mineral with formula: MgFe3+(SO4)2(OH)·7H2O. It is also known as quetenite.
Chlorargyrite is the mineral form of silver chloride (AgCl). Chlorargyrite occurs as a secondary mineral phase in the oxidation of silver mineral deposits. It crystallizes in the isometric - hexoctahedral crystal class. Typically massive to columnar in occurrence it also has been found as colorless to variably yellow cubic crystals. The color changes to brown or purple on exposure to light. It is quite soft with a Mohs hardness of 1 to 2 and dense with a specific gravity of 5.55. It is also known as cerargyrite and, when weathered by desert air, as horn silver. Bromian chlorargyrite is also common. Chlorargyrite is water-insoluble.
Microlite was once known as a pale-yellow, reddish-brown, or black isometric mineral composed of sodium calcium tantalum oxide with a small amount of fluorine. Its chemical formula is(Na,Ca)2Ta2O6(O,OH,F). Today it is a name of a group of oxide minerals of a similar stoichiometry having tantalum prevailing over titanium and niobium. The microlite group belongs to a large pyrochlore supergroup that occurs in pegmatites and constitutes an ore of tantalum. It has a Mohs hardness of 5.5 and a variable specific gravity of 4.2 to 6.4. It occurs as disseminated microscopic subtranslucent to opaque octahedral crystals with a refractive index of 2.0 to 2.2. Microlite is also called djalmaite, but both names are now obsolete.
Livingstonite is a mercury antimony sulfosalt mineral. It occurs in low-temperature hydrothermal veins associated with cinnabar, stibnite, sulfur and gypsum.
Heptasartorite is a very rare mineral with formula Tl7Pb22As55S108. It belongs to sartorite homologous series. It is related to other recently approved minerals of the series: enneasartorite and hendekasartorite. All three minerals come from a quarry in Lengenbach, Switzerland, which is famous of thallium minerals. Chemically similar minerals include edenharterite and hutchinsonite.
Faizievite is a very rare mineral with the formula K2Na(Ca6Na)Ti4Li6Si24O66F2. This triclinic mineral is chemically related to baratovite and katayamalite. Faizievite is a single-locality mineral, coming from the moraine of the Darai-Pioz glacier, Tien Shan Mountains, Tajikistan. Alkaline rocks of this site are famous for containing numerous rare minerals, often enriched in boron, caesium, lithium, titanium, rare earth elements, barium, and others.
Berzelianite is a rare copper selenide mineral with the formula Cu2Se. It occurs as thin dendritic crusts or as fine-grained inclusions. It crystallizes in the isometric system, unlike its dimorph, bellidoite, which crystallizes in the tetragonal system. The crystals are opaque and slightly malleable.
The sulfate chlorides are double salts containing both sulfate (SO42–) and chloride (Cl–) anions. They are distinct from the chlorosulfates, which have a chlorine atom attached to the sulfur as the ClSO3− anion.
The sulfate carbonates are a compound carbonates, or mixed anion compounds that contain sulfate and carbonate ions. Sulfate carbonate minerals are in the 7.DG and 5.BF Nickel-Strunz groupings.