What is 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 called?

tetradymite — 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's 1913.)

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