Formula: Ca3Cr2(SiO4)3
Nesosilicate (insular SiO4 groups),
garnet group, chromium-bearing
mineral
Uvarovite forms a complete solid solution with grossular
Ca3Al2(SiO4)3. This is possible because the ionic radius of Al3+
(0.535 Å) is similar to that of Cr3+ (0.615 Å). The Cr3+ of uvarovite is only partially
replaced by Fe3+ (ionic radius 0.64 Å), and there is not a similar complete solid solution with
andradite
Ca3Fe3+2(SiO4)3
Crystal System: Isometric
Specific gravity: 3.77 to 3.81 measured, 3.848 calculated
Hardness: 6½ to 7
Streak: white
Colour: green, green-black
Solubility: Insoluble in water, hydrochloric, nitric and sulphuric acid
Common impurities: Al,Fe,Mg
Environments:
Uvarovite occurs in metamorphosed chromite deposits and in
skarn.
Localities
At the Outokumpu mine, Finland, uvarovite is found in skarn and
serpentinised sediments (Lauf p137).
Uvarovite from the Outokumpu Mine - Image
At the Saranovskii mine, Perm district, Urals, Russia, uvarovite is quite common, filling cracks in the
chromite ore, associated with calcite,
chromium-rich amesite and other species
(Lauf p137).
Uvarovite from the Saranovskii Mine - Image
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