A mineral, calcium tungstatemolybddate, Ca(WO4MoO4),
an important ore of tungsten. It is found
in metamorphic deposits and in pegmatites.
Scheelite crystallizes in the tetragonal system with bipyramidal crystals,
and also occurs as massive granular aggregates. It reveals various tints
with adamantine luster. Hardness 4.5–5; relative density 6.
AND PLANETARY SCIENCE