Large, brightly fluorescent, pseudo-octahedral scheelite crystal on a matrix of non-fluorescent muscovite plates. From Mt Xuebaoding, Pingwu Co., Sichuan, China; likely collected from the Pukouliang Mine. The size of this specimen is 100 x 89 x 80 mm, and it weighs 591 grams.
Scheelite specimens from the Mt Xuebaoding area were once relatively abundant, but this area is now closed to mining and these beautiful scheelites have become much less common and far more expensive.
In the composite photograph above, the image at left shows the specimen under visible light, while the right image shows the fluorescent response under short wave UV (254 nm).
Detail of the specimen, shown under visible light. Large golden-orange pseudo-octahedral scheelite crystal on a matrix of muscovite plates. This is a well-trimmed specimen with little to no damage.
As shown above, under short wave UV (254 nm), the scheelite crystal shows bright blue/white fluorescence. Tungsten-containing scheelite (calcium tungstate) forms a solid solution series with molybdenum-containing powellite (calcium molybdate). As the molybdenum content increases, the fluorescent response becomes more yellow. Based on the very bright, pure blue/white fluorescence of this specimen, it is likely nearly pure end member scheelite with little to no molybdenum content.