Noun.  (mineral) A mineral with monoclinic crystals of the chemical formula Ca2(Mg,Fe)5Si8O22(OH)2, belonging to the amphibole group.

This is an unmodified, but possibly outdated, definition from Wiktionary and used here under the Creative Commons license.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.