Cavansite in mother rock from the Poona district in India.

Cavansite is a hydrated calcium-vanadium silicate mineral with the formula Ca(V5+O)Si4O10·4H2O. This phyllosilicate falls under the mica group. Cavansite, ranging from green to dark blue, exhibits a glassy luster, a blue-white streak, and cleaves well along the [010] crystal face. It has an average density of 2.25 and a hardness of 3 to 4. The crystal system is orthorhombic, and the mineral is non-radioactive. The name cavansite is taken from the chemical elements that make it up: calcium, vanadium and silicon. Cavansite is mainly found in secondary mineralizations in andesites and basalts. The original site is near the Owyhee Dam in Malheur County, Oregon, USA. Today the Wagholi quarry near Pune in India is the main source.