Chemical Composition : Ca19Al4Fe(Al,Mg,Fe)8Si18O7 Calcium Aluminum Iron Silicate
Hardness : 6.0 – 7.0
Specific Gravity (Density) : 3.32 – 3.47 (g/cm3)
Refractive Index : 1.698 – 1.742 Uniaxial ( -/+ ) and Biaxial
Vesuvianite (also known as Idocrase) is found in colors ranging from green to brown and also a blue variety called Cyprine. The complexities of its chemistry leads to the wide range of colors and properties. The green variety is similar in color to Peridot gems. Cyprine, the blue variety of Vesuvianite, is colored by the addition of copper to its chemistry and is also refered to as Cupreous Idocrase or Cupreous Vesuvianite.
There are many sources of Vesuvianite such as Asbestos, Quebec, Canada; California, Colorado and the New England region of USA; Mt. Vesuvius, Italy; Ural Mountains, Russia, Switzerland, Tanzania and Kenya. However, there are only a few sources of gem quality crystals. A small amount of gemmy material has come from Asbestos, Quebec, Canada. Recent finds in Tanzania and Kenya have brought some very nicely colored gems to the market. One source of material is from California, USA and has been nick-named Californite or California Jade. This bright green opaque to translucent material comes from near Happy Jack mine, Siskiyou County and near Pulga, Butte County, California.