SCHEELITE
Scheelite is a calcium tungstate mineral (CaWO4).
It has a nonmetallic luster, is variably colored, moderately hard (H = 4.5 to
5), has one cleavage plane, is fairly heavy for its size, and fluoresces an
intense blue under ultraviolet light. Scheelite occurs in igneous &
metamorphic rocks, and is a ore mineral for tungsten (W).
Scheelite in matrix (field of view 3.4 cm across) from Timmins, Ontario, Canada.
Left:
scheelite (light brown) under white light.
Right:
scheelite under ultraviolet light; scheelite usually fluoresces a bright blue
under UV.