Mineral - Scheelite
Scheelite
Chemical Properties
Mineral Class
Tungstate
Toxicity
none
Formula
Ca[WO₄]
Unit Cell
a=5.25 c=11.37 Z=4
Physical Properties
Hardness
4.5 - 5
Streak
white
Density
Very Heavy (>6)
Cleavage
Distinct after {101}, indistinct after {001}
Fracture
conchoidal,
uneven
Tenacity
Brittle
Optical Properties
Color
brownredorangeyellow
Birefringence
0.017
Luster
Greasy,
Adamantine
Transparency
translucent,
transparent,
opaque
Pleochroism
Geomineralogical Properties
Crystal System
tetragonal
Point Group
tetragonal-dipyramidal - 4/m
Space Group
I4 1 /a (88)
Habit
dipyramidal, Octahedron, pyramidal
Formation
(1) Magmatic-hydrothermal in granitic skarns through the reaction of fluorine-rich, tungsten-bearing fluids with carbonate host rocks (metasomatism).
(2) Through the impregnation of solutions into high-temperature quartz veins (greisens)
(3) Secondary as an oxidation product of tungsten-bearing primary minerals
Paragenesis
Twinning
Rarity
Rather rare
Synonyms
Scheelite
Composition
Elements
Mass
WO₃
80.17
MoO₃
0.07
MgO
0.01
CaO
19.49
Germany (Palache et al. 1952)
Groups and Members
Scheelite-Group