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Scheelite is a calcium tungstate mineral with the chemical formula Ca W O 4. It is an important ore of tungsten (wolfram). Scheelite is originally named after Swedish chemist Carl Wilhelm Scheele (1742–1786).
The name tungsten (which means ' heavy stone ' in Swedish and was the old Swedish name for the mineral scheelite and other minerals of similar density) is used in English, French, and many other languages as the name of the element, but wolfram (or volfram) is used in most European (especially Germanic and Slavic) languages and is derived from ...
It is also anisotropic and fairly dense (SG 5.9–6.1). Synthetic scheelite produced via the Czochralski process is available, but it has never been widely used as a diamond simulant. Due to the scarcity of natural gem-quality scheelite, synthetic scheelite is much more likely to simulate it than diamond.
Along with scheelite, the wolframite series are the most important tungsten ore minerals. Wolframite is found in quartz veins and pegmatites associated with granitic intrusives. [5] Associated minerals include cassiterite, scheelite, bismuth, quartz, pyrite, galena, sphalerite, and arsenopyrite.
They are up to 5m thick and several metres in strike length, and comprise massive or semi-massive sulphide horizons with scheelite mineralisation. Sulphides comprise pyrite, arsenopyrite , pyrrhotite and chalcopyrite as principal minerals. The four main rock types present at Los Santos are skarn, granite, calc-silicates and corneanas, a word ...
Scheelite is treated similarly using sodium carbonate. Sodium tungstate can also be produced by treating tungsten carbide with a mixture of sodium nitrate and sodium hydroxide in a fusion process which overcomes the high exothermicity of the reaction involved. Several polymorphs of sodium tungstate are known, three at only one atmosphere ...
This compound is isostructural with the mineral scheelite (CaWO 4). [1] Silver perrhenate reacts with trimethylsilyl chloride to give the silyl "ester" (CH 3 ) 3 SiOReO 3 . [ 2 ]
It is a white solid, [3] which at normal conditions forms tetragonal crystals similar to scheelite, CaWO 4. Under pressures above 7 GPa, the compound undergoes transformation to a monoclinic structure similar to fergusonite , YNbO 4 .