biotite Meaning, Definition & Usage

  1. noun dark brown to black mica found in igneous and metamorphic rock

WordNet

Bi"o*tite noun
Etymology
From Biot, a French naturalist.
Definitions
  1. (Min.) Mica containing iron and magnesia, generally of a black or dark green color; -- a common constituent of crystalline rocks. See Mica.

Webster 1913