LEPIDOMELANE
lepidomelane
(noun) a mica that is a biotite containing iron
Source: WordNet® 3.1
Etymology
Noun
lepidomelane (plural lepidomelanes)
(mineral) A black iron-potash mica, usually found in granitic rocks in small six-sided tables, or as an aggregation of minute opaque scales.
Source: Wiktionary
Lep`i*dom"e*lane, n. Etym: [Fr. (Min.)
Definition: An iron-potash mica, of a raven-black color, usually found in
granitic rocks in small six-sided tables, or as an aggregation of
minute opaque scales. See Mica.
Source: Webster’s Unabridged Dictionary 1913 Edition