sillimanite

A Dictionary of Earth Sciences | 1999 | 647 words | Copyright

sillimanite (fibrolite) A nesosilicate and one of an important group of three mineral polymorphs with the same composition Al₂SiO₅, the other two being andalusite and kyanite; sp. gr. 3.23; hardness 6.5–7.5; orthorhombic; occurs as elongate prismatic crystals with a diamond-shaped cross-section or as fibrous and felted masses; colourless; occurs under conditions of high-grade metamorphism either in the innermost zones of thermal aureoles (see CONTACT AUREOLE) or in high-grade regional metamorphic rocks (see REGIONAL METAMORPHISM) formed under high temperatures and pressures. It is named after the American mineralogist B. Silliman.

Cite this article
Pick a style below, and copy the text for your bibliography.

MLA
Chicago
APA

AILSA ALLABY and MICHAEL ALLABY. "sillimanite." A Dictionary of Earth Sciences. 1999. Encyclopedia.com. 27 May. 2012 <http://www.encyclopedia.com>.

AILSA ALLABY and MICHAEL ALLABY. "sillimanite." A Dictionary of Earth Sciences. 1999. Encyclopedia.com. (May 27, 2012). http://www.encyclopedia.com/doc/1O13-sillimanite.html

AILSA ALLABY and MICHAEL ALLABY. "sillimanite." A Dictionary of Earth Sciences. 1999. Retrieved May 27, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O13-sillimanite.html

Learn more about citation styles