Zoisite, first known as saualpite, after its type locality, is a calcium aluminum hydroxy sorosilicate belonging to the epidote group of minerals.

Zoisite occurs as prismatic, orthorhombic (2/m 2/m 2/m) crystals or in massive form, being found in metamorphic and pegmatitic rock.

Zoisite may be blue to violet, green, brown, pink, yellow, gray, or colorless.

[6] Sources of zoisite include Tanzania (tanzanite), Kenya (anyolite), Norway (thulite), Switzerland, Austria, India, Pakistan, and the U.S. state of Washington.

More recently, the Thulite variety has been found in Canada, in the Jeffrey Mine (Val-des-sources, QC) and in British Columbia.