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.

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