- zoisite
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/zoy"suyt/, n. Mineral.an orthorhombic dimorph of clinozoisite.[1795-1805; named after Baron S. Zois von Edelstein (1747-1819), Slovenian nobleman who discovered it; see -ITE1]
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▪ mineralsilicate mineral, calcium and aluminum silicate, Ca2Al3(SiO4)3OH, characteristic of regional metamorphism and of hydrothermal alteration of igneous rocks. A member of the epidote (q.v.) group of nesosilicates, zoisite occurs as white, green-brown, or gray crystals or masses in crystalline schists, often with amphibole minerals; in metamorphosed calcareous shales; very commonly in argillaceous (clayey) calcareous sandstones; and less commonly in thermally metamorphosed limestone. Occurrences include Italy, Germany, Switzerland, Mexico, Scotland, and the United States (Massachusetts). thulite, a manganous variety from Telemark, Nor., and Piedmont, Italy, is pink; tanzanite, a gem variety from Tanzania, is vivid blue. Zoisite has the same chemical formula as clinozoisite but has a different crystal structure. For detailed physical properties, see silicate mineral (table).* * *
Universalium. 2010.