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Scheelite is a calcium tungstate mineral with the chemical formula CaWO4.

Scheelite

It is an important ore of tungsten. Well-formed crystals are sought by collectors and are occasionally fashioned into gemstones when suitably free of flaws. Scheelite has been synthesized via the Czochralski process; the material produced may be used to imitate diamond, as a scintillator, or as a solid state lasing medium.
Composition
The scheelite structure consists of isolated tetrahedra. The tetrahedra form (non touching) 1D chains. There are two directions that the "chains" line up. Tungsten deposits only occur where mineralization has taken place at high temperatures and pressures. Research shows these were deposited mostly between 200 to 500 degrees Celsius, and from 200 to 1,500 bars.
Special Characteristics
Scheelite is often found to have a grayish white color; yellowish, brownish or translucent. Its streak is white. Scheelite has a greasy luster which helps distinguish it. Moreover, when looking for scheelite, miners use ultraviolet light which causes it to fluoresce with a bright blue color. Many prospectors for scheelite have made good use of scheelite's typically bright blue fluorescence by searching for scheelite deposits by night with ultraviolet lamps. Many old mines have even been reopened after examination of the mine shafts with ultraviolet lamps have proven that the ore is not quite yet exhausted.

钨酸盐矿物。成分为Ca[WO4]。含WO380.6％，与黑钨矿同为钨的最主要工业矿物。四方晶系，晶体为近于八面体的四方双锥；通常呈不规则粒状或致密块状集合体。无色或白色，一般多呈灰色、浅黄、浅紫或浅褐色。玻璃光泽到金刚光泽，断口呈油脂光泽。解理中等，断口参差状。莫氏硬度4.5 ～5，比重大，达6.1。在紫外线照射下发浅蓝色荧光。主要产于花岗岩与石灰岩的接触交代夕卡岩中。中国湖南瑶岗仙和朝鲜南部的山塘都是世界有名的夕卡岩型白钨矿床。
　　白钨矿过去叫钙钨矿或钨酸钙矿，它是重要的钨矿，是钙的钨酸盐矿物。钨被用于合金钢和我们熟悉的电灯灯丝。1781年瑞典化学家从白钨矿中提取了钨酸。白钨矿常常呈一种致密的块状或不规则的粒状，有白色、黄色、褐色、绿色、无色等，具有玻璃光泽。多数白钨矿都能发出荧光来，颜色在蓝、白、黄之间变化。颜色变化是因为其内部所含的钼或多或少。
　　化学组成：CaWO4,CaO19.47%，WO380.53%；
　　鉴定特征：以色浅，油脂光泽，比重大、在紫外线下发出淡蓝色荧光和难熔的特征作为鉴定特征；
　　成因产状：主要产出于接触交代矿床中，与石榴子石，符山石，透辉石等矿物伴生，或产于高温热液中与黑钨矿等伴生；
　　著名产地：世界著名的产地有中国四川平武；德国的Saxony、Bohemia；英国的Cornwall；澳洲的NewSouthWales、Queensland；玻利维亚的北部；美国的Nevada，Arizona和California等州；加拿大的BritishColumbia、Yukon和NorthwestTerritories边界的东方等地。
　　名称来源：用来纪念一位18世纪最早发现钨的瑞典化学家K.W.Scheele(1742-1786)，而以其名字命名；
晶体形态
　　四方双锥晶类，晶形常呈近于八面体的四方双锥，也有沿呈板状。主要单形为四方双锥e和p，四方双锥e的晶面常具斜纹和蚀象。依（110）成双晶。
晶体结构
　　晶系和空间群：四方晶系，4/m；
　　晶胞参数：a0=5.25Å，c=11.40Å；
　　粉晶数据：3.1(1)4.76(0.55)3.072(0.3)
物理性质
　　硬度：4.5
　　比重：6.1g/cm3
　　解理：解理
　　断口：参差状断口
　　颜色：灰色、浅黄色、浅紫色或浅褐色，有时带有绿色、桔黄色或红色
　　条痕：黄绿色
　　透明度：透明到半透明
　　光泽：油脂光泽或金刚光泽
　　发光性：荧光,UV短波为亮蓝白色.
　　其他：在短波紫外光下，此矿物发出鲜艳的蓝白荧光