glaucophane
Noun. (mineralogy) A mixed aluminate of sodium, magnesium and aluminium that has a characteristic blue colour, and exhibits pleochroism, with the chemical formula Na2(Mg,Fe2+)3Al2Si8O22(OH)2.This is an unmodified, but possibly outdated, definition from Wiktionary and used here under the Creative Commons license. Wiktionary is a great resource. If you like it too, please donate to Wikimedia.
This entry was last updated on RefTopia from its source on 3/20/2012.