Formula: {Ca2}{Al3}(Si2O7)(SiO4)O(OH)
Colour: Colourless, purple, greyish-white, grey, yellowish-brown, yellow, pink, green
Lustre: Vitreous
Hardness: 6 - 7
Specific Gravity: 3.15 - 3.36
Crystal System: Orthorhombic
Name: Originally named saualpite for the locality Saualpe in Carinthia, Austria, where it occurs in eclogites. The name zoisite was introduced by A.G. Werner in 1805 to honour Sigmund Zois, Baron von Edelstein (1747-1819), Austrian scholar who financed mineral-collecting expeditions. It was from Baron Zois that Werner obtained the holotype specimen from Saualpe (found by mineral dealer Simon Prešern in 1804).