Uvarovite

Uvarovite
General
CategoryNesosilicate
FormulaCa3Cr2Si3O12
IMA symbolUv
Strunz classification9.AD.25
Crystal systemCubic
Crystal classHexoctahedral (m3m)
H-M symbol: (4/m 3 2/m)
Space groupIa3d
Unit cella = 11.99 Å; Z = 8
Identification
ColorGreen, emerald-green, green-black
Crystal habitEuhedral crystals, granular, massive
FractureUneven, conchoidal
Mohs scale hardness6.5–7.5
LusterVitreous
StreakWhite
DiaphaneityTransparent, translucent
Specific gravity3.77–3.81
Optical propertiesIsotropic
Refractive indexn = 1.865
Other characteristicsFluorescent red in both short and long UV
References

Uvarovite is a chromium-bearing garnet group species with the formula: Ca3Cr2(SiO4)3. It was discovered in 1832 by Germain Henri Hess who named it after Count Sergei Uvarov (1765–1855), a Russian statesman and amateur mineral collector. It is classified in the ugrandite group alongside the other calcium-bearing garnets andradite and grossular.

Uvarovite is the rarest of the common members of the garnet group, and is the only consistently green garnet species, with an emerald-green color. It occurs as well-formed fine-sized crystals.