Vesuvianite

Vesuvianite, also known as idocrase, is a green, brown, yellow, or blue silicate mineral. It occurs as tetragonal crystals in skarn deposits and limestones that subjected to contact metamorphism.

It first discovered within included blocks or adjacent to lavas on Mount Vesuvius, hence its name. Attractive-looking crystals sometimes cut as gemstones. Localities which have yielded fine crystallized specimens include Mount Vesuvius and the Ala Valley near Turin, Piedmont.

The specific gravity is 3.4 and the hardness 6.5. The name “vesuvianite” given by A. G. Werner in 1795, because fine crystals of the mineral found at Vesuvius; these brown in color and occur in the ejected limestone blocks of Monte Somma.