Schreyerite
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Schreyerite (V2Ti3O9), is a vanadium, titanium oxide mineral found in the Lasamba Hill, Kwale district in Coast Province, Kenya. It is polymorphous with kyzylkumite.
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Schreyerite | |
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General | |
Category | Oxide mineral |
Formula (repeating unit) | V2Ti3O9 |
IMA symbol | Sry[1] |
Strunz classification | 4.CB.35 |
Crystal system | Monoclinic |
Crystal class | Prismatic (2/m) (same H-M symbol) |
Space group | C2/c |
Unit cell | a = 7.06 Å, b = 5.01 Å c = 18.74 Å; β = 119.4°; Z = 4 |
Identification | |
Color | Reddish brown; gray in reflected light |
Crystal habit | As lamellae and microscopic grains, exsolved within rutile crystals |
Twinning | Polysynthetic, universal |
Mohs scale hardness | 7 |
Luster | Metallic |
Diaphaneity | Opaque |
Optical properties | Biaxial |
Refractive index | n = 2.700 |
Pleochroism | Weak; yellow-brown to reddish brown |
References | [2][3][4] |
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The mineral occurs as exsolution lamellae and particles in rutile, coexisting with kyanite, sillimanite, and tourmaline in a highly metamorphosed gneiss. It was named after German mineralogist and petrologist Werner Schreyer, for his research on mineralogy of rock-forming minerals and petrology of metamorphic rocks both in nature and by experiment.