Vesuvianite

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Vesuvianite
Vesuvianite Asbestos.jpg
Vesuvianite from the Jeffrey Mine in Asbestos, Quebec
General
CategorySorosilicate
Formula
(repeating unit)
Ca10(Mg, Fe)2Al4(SiO4)5(Si2O7)2(OH,F)4
Strunz classification09.BG.35
Crystal symmetryTetragonal 4/m 2/m 2/m
Unit cella = 15.52 Å, c = 11.82 Å; Z = 2
Identification
ColorYellow, green, brown; colorless to white, blue, violet, bluish green, pink, red, black, commonly zoned
Crystal habitShort pyramidal to long prismatic crystals common, massive to columnar
Crystal systemTetragonal
TwinningFine twin domains observed
CleavagePoor on {110} and {100} very poor on {001}
FractureSub conchoidal to irregular
Mohs scale hardness6 - 7
LusterVitreous to resinous
StreakWhite
DiaphaneitySubtransparent to Translucent
Specific gravity3.32 - 3.43
Optical propertiesUniaxial (-)
Refractive indexnω = 1.703 - 1.752 nε = 1.700 - 1.746
Birefringence0.004-0.006
Pleochroismslight in colored varieties
SolubilityVesuvianite is virtually insolouble in acids
Other characteristicsstriated lengthwise
References[1][2]
 
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Vesuvianite
Vesuvianite Asbestos.jpg
Vesuvianite from the Jeffrey Mine in Asbestos, Quebec
General
CategorySorosilicate
Formula
(repeating unit)
Ca10(Mg, Fe)2Al4(SiO4)5(Si2O7)2(OH,F)4
Strunz classification09.BG.35
Crystal symmetryTetragonal 4/m 2/m 2/m
Unit cella = 15.52 Å, c = 11.82 Å; Z = 2
Identification
ColorYellow, green, brown; colorless to white, blue, violet, bluish green, pink, red, black, commonly zoned
Crystal habitShort pyramidal to long prismatic crystals common, massive to columnar
Crystal systemTetragonal
TwinningFine twin domains observed
CleavagePoor on {110} and {100} very poor on {001}
FractureSub conchoidal to irregular
Mohs scale hardness6 - 7
LusterVitreous to resinous
StreakWhite
DiaphaneitySubtransparent to Translucent
Specific gravity3.32 - 3.43
Optical propertiesUniaxial (-)
Refractive indexnω = 1.703 - 1.752 nε = 1.700 - 1.746
Birefringence0.004-0.006
Pleochroismslight in colored varieties
SolubilityVesuvianite is virtually insolouble in acids
Other characteristicsstriated lengthwise
References[1][2]

Vesuvianite, also known as idocrase, is a green, brown, yellow, or blue silicate mineral. Vesuvianite occurs as tetragonal crystals in skarn deposits and limestones that have been subjected to contact metamorphism.[2] It was first discovered within included blocks or adjacent to lavas on Mount Vesuvius, hence its name.

A bluish variety known as cyprine has been reported from Franklin, New Jersey and other locations; the blue is due to impurities of copper. Californite is a name sometimes used for jade-like vesuvianite, also known as California-, American- or Vesuvianite-jade. Xanthite is a manganese rich variety. Wiluite is an optically positive variety from Wilui, Siberia. Idocrase is an older synonym sometimes used for gemstone-quality vesuvianite.

Tumbled vesuvianite pebble

References[edit]