from The American Heritage® Dictionary of the English Language, 5th Edition.

  • noun A gray, brown, pink, or blue mineral, Ca2Al3(SiO4)3(OH), used in ornamental stonework.

from The Century Dictionary.

  • noun A mineral closely related to epidote, but orthorhombic in crystallization.

from the GNU version of the Collaborative International Dictionary of English.

  • noun (Min.) A grayish or whitish mineral occurring in orthorhombic, prismatic crystals, also in columnar masses. It is a silicate of alumina and lime, and is allied to epidote.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

  • noun mineralogy A mineral with orthorhombic crystals, Ca2Al3(SiO4)(Si2O7)O(OH).


from The American Heritage® Dictionary of the English Language, 4th Edition

[German Zoisit, after Baron Sigismund Zois, von Edelstein (1747–1819), Slovenian noble.]

from Wiktionary, Creative Commons Attribution/Share-Alike License

Named after Austrian scientist Baron Sigmund Zois von Edelstein (1747-1819) in 1805. -ite


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  • The severe crushing to which the rock has been subjected has resulted in the conversion of the plagioclase into scapolite and also in the formation of zoisite by the characteristic alteration of the lime bearing silicate of the feldspar in conjunction with other constituents of the rock.

    The Long Labrador Trail

  • When a blue zoisite came across Tiffany & Co.'s desk in the late 1960s, the company was quick to identify a fatal flaw.

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  • (i) Merelani in Kiteto District, Arusha Region - famous for the mining of tanzanite (a blue-violet zoisite).

    4. Small Scale Gemstone Mining


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  • Zoisite is a calcium aluminium hydroxy sorosilicate belonging to the epidote group of minerals. Its chemical formula is Ca2Al3(SiO4)(Si2O7)O(OH). Zoisite is named after the Slovene scientist Baron Sigmund Zois von Edelstein, who realized that this was an unknown mineral when it was brought to him by the mineral dealer Simon Prešern, who had discovered it in the Saualpe mountains of Carinthia in 1805. Transparent material is fashioned into gemstones while translucent-to-opaque material is usually carved into sculptural works. The latter is sometimes shot through with ruby crystals, which are completely opaque and unsuited to use as gems, yet are well colored and contrast strikingly against the green matrix of the zoisite.


    February 14, 2008