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Vesuvianite



Vesuvianite

General
CategoryMineral
Chemical formulaCa10(Mg, Fe)2Al4(SiO4)5(Si2O7)2(OH,F)4
Identification
Molecular Weight1,422.09 gm
ColorYellow, green, brown - rarely blue or red
Crystal habitMassive to columnar
Crystal systemTetragonal
CleavagePoor to very poor
FractureSub conchoidal
Mohs Scale hardness6.5
LusterVitreous to resinous
Refractive indexnω = 1.702 - 1.742 nε = 1.698 - 1.736
Optical PropertiesUniaxial (-)
Birefringence0.0040-0.0060
Pleochroismslight in colored varieties
StreakWhite
Specific gravity3.35 - 3.45
SolubilityVesuvianite is virtually insolouble in acids
DiaphaneitySubtransparent to Translucent
Other Characteristicsstriated lengthwise

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. It was first discovered within included blocks or adjacent to lavas on Mount Vesuvius, hence it's name.

Additional recommended knowledge

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.

References

  • Deere, W. A. et al., 1962, Rock Forming Minerals: Vol. 1 Ortho- and Ring Silicates, pp. 113 - 120
  • Webmineral data
  • Mineral galleries
  • Mindat with location data
  • Vesuvianite at Franklin -Sterling
  • Mindat - Cyprine var. w/ location data
 
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Vesuvianite". A list of authors is available in Wikipedia.
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