scheelite


Also found in: Dictionary, Thesaurus, Medical, Wikipedia.
Related to scheelite: tungsten

scheelite

(shā`līt, shē`–), heavy white or yellow mineral, calcium tungstate, CaWO4, crystallizing in the tetragonal system. It is found in granite pegmatites, in contact-metamorphic deposits (especially limestones intruded by granites), and in quartz veins. It is an important ore of tungsten and is mined in many parts of the world. Scheelite fluoresces bright bluish-white in ultraviolet radiation, a distinguishing feature utilized in prospecting and mining.

Scheelite

 

(named after K. W. Scheele), a mineral of the tungstate class, with a chemical composition CaWO4. Admixtures include Mo (up to 25 atomic percent in molybdoscheelite and more than 25 atomic percent in seyrigite), Cu (up to 25 atomic percent in cuproscheelite), Sr, Mn, Nb, Ta, and F.

Scheelite crystallizes in the tetragonal system, forming dipyramidal crystals; penetration twins are known to exist. Grains and granular masses are common, and pseudomorphs of scheelite after wolframite often occur. Scheelite may be colorless, white, gray, yellowish, or, more rarely, brown, green, or black in color, with a greasy to adamantine luster. It is brittle and has perfect cleavage. The hardness varies from 3 to 5 on Mohs’ scale, and the density is 5,500–6,170 kg/m3. The mineral’s luminescence in ultraviolet light (ranging from bright blue to yellow) is related to the Mo content.

The largest agglomerations of scheelite are confined to skarns, where the mineral occurs in association with garnet, pyroxene, plagioclase, amphibole, quartz, molybdenite, and other minerals. It is commonly found in high-temperature greisens, quartz-ore veins, and stockworks together with wolframite, cassiterite, fluorite, gold, and other minerals. In low-temperature hydrothermal deposits, it is associated with ferberite, antimonite, or cinnabar. Accessory scheelite has been found in granites and metamorphic rocks. Scheelite also sometimes occurs in pegmatites and alpine veins, as well as in the oxidation zone; it is converted to alluvial deposits upon weathering. Scheelite is the most important ore of tungsten; it also serves as an ore of molybdenum. The largest deposits are located in the USSR, the United States, and Korea.

REFERENCE

Bybochkin, A. M. Mestorozhdeniia vol’frama i zakonomernosti ikh razmeshcheniia. Moscow, 1965.

O. V. KONONOV

scheelite

[′shā‚līt]
(mineralogy)
CaWO4 A yellowish-white mineral crystallizing in the tetragonal system and occurring in tabular or massive form in pneumatolytic veins associated with quartz; an ore of tungsten.
References in periodicals archive ?
063 mm fraction at the Sisson deposit also contain up to 150,000 scheelite grains/10 kg in the pan concentrate fraction (Appendix A), with most grains between 25 and 200 pm in size (McClenaghan et al.
Meanwhile, the Sandaozhuang molybdenum and tungsten mine has a reserve of approximately 407,200 tonnes of scheelite associated with molybdenum, making it the second largest scheelite mine in China after Shizhuyuan scheelite mine.
2, which indicated that monoclinic scheelite structure was an only XRD-detactable phase for all powders prepared in this experiment.
These Scheelite veins occur within the current gold mineralized footprint at Monument Bay and could become a significant economic by-product (University of Manitoba Presentation Nov 2012).
As per the initial definitive feasibility study, the Molyhil mine could produce some 400 000 t/y, delivering 2 200 t/y of scheelite product and 1 250 t/y of molybdenum concentrate.
Tungsten is the common link, with almost all of the discovered mineral systems at Falcon and Cuttaburra having significant scheelite mineralisation.
The tungsten mineral of primary economic interest is wolframite (Fe,MnWO4), with minor amounts of scheelite (CaWO4).
hk) published a letter of intent on initiating offering of not more than 542 million A shares with proceeds of RMB3,646 million to be raised, which will be invested in four major projects, namely, the "Clean and Efficient Resource Integrated Utilisation and Construction Project with an Annual Processing Capacity of 42,000 Tonnes of Low-grade and Complex Scheelite Ores", the Ammonium Molybdate Production Line Project with an Annual Production Capacity of 10,000 Tonnes,the High-performance Cemented Carbide Project and the Deep Processing Project of Tungsten Products and Tungsten Alloy Materials.
4 King Island Scheelite Limited (KIS) - Dolphin Project 4.
The company's drill reports from this summer's exploration activities on its Scheelite Dome property in Canada's Yukon Territory indicate the possibility of yet another major gold deposit there.
In a sign of growing confidence in Tasmania, King Island Scheelite Ltd is moving ahead with plans to reopen a mine at Grassy on King Island.
The Company is very pleased with the results of this test work as it demonstrates a high tungsten recovery, by world standards, into a premium grade scheelite concentrate.