Biotite
- n. Mica containing iron and magnesia, generally of a black or dark green color; — a common constituent of crystalline rocks. See Mica.
The word meanings were obtained from OPTED(The Online Plain Text English Dictionary), which is based on “The Project Gutenberg Etext of Webster’s Unabridged Dictionary” which is in turn based on the 1913 US Webster’s Unabridged Dictionary (See Project Gutenburg), as a text file.