tetradymite Meaning, Definition & Usage

Tet*rad"y*mite noun
Etymology
Gr. fourfold. So named from its occurrence in compound twin crystals, or fourlings.
Definitions
  1. (Min.) A telluride of bismuth. It is of a pale steel-gray color and metallic luster, and usually occurs in foliated masses. Calles also telluric bismuth.

Webster 1913