A valuable, transparent, blue-violet type of zoisite resembling sapphire It is often heat-treated in order to produce a deeper blue-violet colour
Tanzanite (strontium-rich Calcium-aluminum silicate) is a valuable, transparent, blue-violet type of zoisite resembling sapphire Tanzanite has a hardness of 6 and a specific gravity of 3 35 It is often heat-treated in order to produce a deeper blue-violet color This mineral was discovered in 1967 by Manuel d'Souza (an Indian tailor) southwest of Mt Kilimanjaro in Tanzania, Africa