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Kassite (mineral)

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Kassite
Light yellow kassite's spherules with orange-yellow tabular cafetite in lizardite matrix. Base 2 mm. Locality: Val di Serra Quarry, Pilcante, Ala, Lagarina Valley, Trento Province, Trentino-Alto Adige (Trentino-Südtirol), Italy
General
CategoryHydroxide mineral
Formula
(repeating unit)
CaTi2O4(OH)2
Strunz classification4.DH.10
Dana classification08.03.09
Crystal systemMonoclinic
Crystal classPrismatic (2/m)
(same H-M symbol)
Space groupP21/a
Identification
Formula mass235.09 g/mol
ColorBrown red, colorless, light yellow
Crystal habitPseudo hexagonal
Twinning
Common, on {101} and {181}.
Cleavage{010} Perfect, {101} Indistinct
FractureBrittle
TenacityVery brittle
Mohs scale hardness5
LusterAdamantine
StreakWhite
Specific gravity3.42
Density3.42
Optical propertiesBiaxial (–), 2V=58°, dispersion very strong, r > v
Refractive indexnα = 1.95, nβ = 2.13, nγ = 2.21
Birefringenceδ = 0.26
Pleochroismnone
Other characteristicsNot radioactive
References[1][2]

Kassite is a rare mineral whose chemical formula is CaTi2O4(OH)2. It crystallizes in the orthorhombic crystal system and forms radiating rosettes and pseudo-hexagonal tabular crystals which are commonly twinned. Kassite crystals are brownish pink to pale yellow in color, are translucent, and have an adamantine luster. Cleavage is distinctly visible, and the crystals are very brittle.

It was first described in 1965 in the Afrikanda pyroxenite massif, a formation on Russia's Kola Peninsula and was named for Nikolai Grigorievich Kassin (1885–1949), a prominent Russian geologist. It occurs as miarolytic cavity fillings of alkalic pegmatites in the Kola occurrence and in nepheline syenite in the Magnet Cove igneous complex of Arkansas, US. Its mineral association includes cafetite (which with it is also polymorphous), perovskite, titanite, rutile and ilmenite.

References

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