What is "idocrase"

Vesuvianite \Ve*su"vi*an*ite\, n. (Min.) A mineral occurring in tetragonal crystals, and also massive, of a brown to green color, rarely sulphur yellow and blue. It is a silicate of alumina and lime with some iron magnesia, and is common at Vesuvius. Also called idocrase.

n. (context geology English) vesuvianite

n. a green or yellow or brown mineral consisting of a hydrated silicate; it occurs as crystals in limestone and is used a gemstone [syn: vesuvianite, vesuvian]