Search results
Results from the WOW.Com Content Network
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). Well-formed crystals are sought by collectors and are occasionally fashioned into gemstones when suitably free of flaws.
An example of the tetragonal crystals, wulfenite Two different views (top down and from the side) of the unit cell of tP30-CrFe (σ-phase Frank–Kasper structure) that show its different side lengths, making this structure a member of the tetragonal crystal system.
Charge carrier density, also known as carrier concentration, denotes the number of charge carriers per volume. In SI units, it is measured in m −3. As with any density, in principle it can depend on position. However, usually carrier concentration is given as a single number, and represents the average carrier density over the whole material.
It forms a solid solution series with scheelite (calcium tungstate, CaWO 4). It has refractive index values of n ω =1.974 and n ε =1.984. [3] Powellite was first described by William Harlow Melville in 1891 for an occurrence in the Peacock Mine, Adams County, Idaho, and named for American explorer and geologist, John Wesley Powell (1834 ...
Its associated minerals include pyrite, chalcopyrite, quartz, anhydrite, fluorite, and scheelite. Important deposits include the disseminated porphyry molybdenum deposits at Questa, New Mexico and the Henderson and Climax mines in Colorado. Molybdenite also occurs in porphyry copper deposits of Arizona, Utah, and Mexico.
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.
A Maryland man was arrested after authorities allege he admitted to killing his girlfriend, who had been missing. On Sunday, Jan. 19, police investigating the disappearance of 29-year-old Alexis ...
Mittersill is the largest scheelite deposit in Europe, having in 2010 estimated reserves of 6.1 million tonnes of ore grading 0.5% pure tungsten. [ 3 ] [ 4 ] The mine produces around 500.000 t ore grading 0.3 %WO 3 , i.e., around 1,200 tonnes of WO 3 per year (data from 2010 to 2017) .