Minerals identify

Know how to recognize them

Tetradymite

Sulfide mineral

Tetradymite is a mineral , tellurium 2S is absent the mineral is tellurobismuthite and the formula is then Bi2Te3. Traces of selenium

Crystals are rhombohedral , but are rarely distinctly developed; they are twinned together in groups of four; hence the name of the mineral, from the Greek for fourfold. There is a perfect cleavage parallel to the basal plane and the mineral usually occurs in foliated masses of irregular outline. The color is steel-gray, and the luster metallic and brilliant. The mineral is very soft (H = 1.5 – 2) and marks paper. The specific gravity is 7.2 to 7.9.

The type locality is Zupkov (Zsubko; Schubkau), Stredoslovenský Kraj, Slovak Republic It was first found, in 1815, at Telemark It often occurs in high temperature hydrothermal veins and in contact metamorphic

Identification

Color of mineral

Grey
White

Mohs scale ( mineral hardness )

1.5

Luster ( interacts light )

Metallic
Dull

Crystal ( diaphaneity )

Trigonal