Tetradymite \Tet*rad"y*mite\, n. [Gr. tetra`dymos fourfold. So
named from its occurrence in compound twin crystals, or
fourlings.] (Min.)
A telluride of bismuth. It is of a pale steel-gray color and
metallic luster, and usually occurs in foliated masses.
Called also {telluric bismuth}.
[1913 Webster]