Vesuvianite
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Vesuvianite | |
---|---|
General | |
Category | Mineral |
Chemical formula | Ca10(Mg, Fe)2Al4(SiO4)5(Si2O7)2(OH,F)4 |
Identification | |
Molecular Weight | 1,422.09 gm |
Color | Yellow, green, brown - rarely blue or red |
Crystal habit | Massive to columnar |
Crystal system | Tetragonal |
Cleavage | Poor to very poor |
Fracture | Sub conchoidal |
Mohs Scale hardness | 6.5 |
Luster | Vitreous to resinous |
Refractive index | nω = 1.702 - 1.742 nε = 1.698 - 1.736 |
Optical Properties | Uniaxial (-) |
Birefringence | 0.0040-0.0060 |
Pleochroism | slight in colored varieties |
Streak | White |
Specific gravity | 3.35 - 3.45 |
Solubility | Vesuvianite is virtually insolouble in acids |
Diaphaneity | Subtransparent to Translucent |
Other Characteristics | striated 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.
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.
[edit] 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