Zoisite is a mineral primarily consisting of calcium and aluminum. It was discovered in 1805 in the Austrian sau-alps, by the scientist Baron Sigmund Zois von Edelstein (after whom the mineral has been named). This mineral naturally occurs in many colors--varying from blue to violet, green, pink or brown--and is commonly used as a gemstone (in the case of transparent variety) or carved into sculptural works (in the case of translucent to opaque variety). Some of the other names by which zoisite is also known are illuderite, ortho-zoisite or unionite.
Chemical Composition
Zoisite is a calcium aluminum hydroxy sorosilicate compound and is closely associated with the epidote mineral group, given its similarity in the crystal angles and structure as well as the chemical composition. It has a molecular weight of 454.36 gms, with 17.64 percent calcium (present as 24.68 percent calcium oxide), 17.82 percent aluminum (present as 33.66 percent alumina), 18.54 percent silicon (present as 39.67 percent silica), 0.22 percent hydrogen (present as 1.98 percent water) and 45.78 percent oxygen.
Properties
Zoisite has a vitreous luster and has a hardness that is somewhere between 6 and 7 on the Mohs scale, while its specific gravity is between 3.10 and 3.38. It is brittle in nature and has a density of 3.15 to 3.36 grams per cubic cm. It has an uneven to conchoidal fracture.
Source
Zoisite generally occurs in metamorphic or pegmatitic rock types, and most commonly occurs as a columnar or compact mass. Although it was first discovered in the Austrian alps, the most common sources of zoisite are in Tanzania (where it is called tanzanite and is a blue-purple variety), Kenya (called anyolite), Norway (called thulite and is pink in color), Switzerland, India, Pakistan and the U.S.
Metaphysical Beliefs
Zoisite is a popular gemstone, as some people believe it to have many metaphysical properties. It is thought to dispel negative energies, give power to manifest oneself and transform destructive tendencies into constructive strength. It is also believed to assist in recovery from severe illness or stress. Further, zoisite is believed to be a detoxifier, and is thought to give strength to the immune system.
Impurities
Zoisite most commonly occurs as a prismatic, orthorhombic crystal. Some of the impurities present in the mineral include iron, manganese, magnesium, chromium, titanium, calcium, sodium, vanadium, strontium and water.
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