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epidote
epidote (pistacite) A rock-forming mineral Ca2(Al2Fe3+)Si3O12(OH) and a member of the epidote group of minerals, which includes zoisite, clinozoisite, and allanite; sp. gr. 3.4–3.5; hardness 6.5; monoclinic; normally pistachio-green, but also various shades of green, yellow, grey, or black; vitreous lustre; crystals are prismatic parallelograms, often rod-like and isometric, often showing radial, fibrous, and columnar masses; cleavage perfect zoisite; it occurs in hydrothermal formations, especially associated with altered, basic, igneous rocks, and also in contact metamorphic zones with quartz, chlorite, calcite, and sulphides, and can also replace various minerals, such as amphiboles, which break down under late-stage hydrothermal alteration.
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Cite this article
AILSA ALLABY and MICHAEL ALLABY. "epidote." A Dictionary of Earth Sciences. 1999. Encyclopedia.com. 27 May. 2012 <http://www.encyclopedia.com>. AILSA ALLABY and MICHAEL ALLABY. "epidote." A Dictionary of Earth Sciences. 1999. Encyclopedia.com. (May 27, 2012). http://www.encyclopedia.com/doc/1O13-epidote.html AILSA ALLABY and MICHAEL ALLABY. "epidote." A Dictionary of Earth Sciences. 1999. Retrieved May 27, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O13-epidote.html |
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zoisite
zoisite Member of the epidote group of minerals, with the formula Ca2Al3Si3O12OH; sp. gr. 3.3; hardness 6.5; greyish-white or greenish; crystals orthorhombic, prismatic, but normally massive or columnar; occurs in regional-metamorphic (see REGIONAL METAMORPHISM) rocks. Thulite is a rose-pink variety.
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Cite this article
AILSA ALLABY and MICHAEL ALLABY. "zoisite." A Dictionary of Earth Sciences. 1999. Encyclopedia.com. 27 May. 2012 <http://www.encyclopedia.com>. AILSA ALLABY and MICHAEL ALLABY. "zoisite." A Dictionary of Earth Sciences. 1999. Encyclopedia.com. (May 27, 2012). http://www.encyclopedia.com/doc/1O13-zoisite.html AILSA ALLABY and MICHAEL ALLABY. "zoisite." A Dictionary of Earth Sciences. 1999. Retrieved May 27, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O13-zoisite.html |
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pistacite
pistacite See EPIDOTE.
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Cite this article
AILSA ALLABY and MICHAEL ALLABY. "pistacite." A Dictionary of Earth Sciences. 1999. Encyclopedia.com. 27 May. 2012 <http://www.encyclopedia.com>. AILSA ALLABY and MICHAEL ALLABY. "pistacite." A Dictionary of Earth Sciences. 1999. Encyclopedia.com. (May 27, 2012). http://www.encyclopedia.com/doc/1O13-pistacite.html AILSA ALLABY and MICHAEL ALLABY. "pistacite." A Dictionary of Earth Sciences. 1999. Retrieved May 27, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O13-pistacite.html |
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