tetradymite
noun
te·trad·y·mite
| \ tə̇‧ˈtradəˌmīt\
plural -s
Definition of tetradymite
: a mineral Bi2Te2S consisting of a telluride and sulfide of bismuth, sometimes containing selenium, being pale steel gray in color and of a metallic luster, and occurring usually in foliated masses (hardness 1.5–2, specific gravity 7.2–7.6)
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