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Uvarovite

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Uvarovite
Uvarovite druse from Urals Region, Russia (size: 18.3 x 13.1 x 2.0 cm)
General
CategoryNesosilicate
Formula
(repeating unit)
Ca3Cr2Si3O12
Strunz classification9.AD.25
Crystal systemCubic
Space groupIsometric – hexoctahedral
H-M symbol (4/m32/m)
Space group: I a3d
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[1][2][3]

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 Semenovitch Uvarov (1765–1855), a Russian statesman and amateur mineral collector.[1]

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

It is found associated with chromium ores in Spain, Russia, and Quebec in Canada. It also occurs in Finland, Norway, and South Africa.

Pendant in uvarovite, a rare bright-green garnet. The long dimension is 2 cm (0.8 inch)

See also

References