Bismuth

Formula:  Bi

Origin of name:  From German, probably for white mass, weisse Masse, later Wismuth

Crystal system:  Hexagonal

Crystal class:  -3 2/m

Twinning:  Common on {10-14}, polysynthetic

Unit cell: a = 4.55 Ǻ, c = 11.86 Ǻ

Colour:  Silver-white with pinkish tint; tarnishes iridescent

Diaphaneity: Opaque

Luster:  Metallic

Habit:  Crystals indistinct; massive, reticulated, branching, foliated

Hardness:  2 to 2.5

Specific gravity:  9.70 to 9.83

Cleavage:  3; {0001} perfect, {10-11} good, {10-14} imperfect

Tenacity:  Brittle, sectile

Streak:  Silver-white

Synonyms/varieties:

Comments: Found in hydrothermal veins with ores of Co, Ni, Ag and Sn, in pegmatites and topaz-bearing Sn-W quartz veins