Wittite

Formula: Pb₉Bi₁₂(S,Se)₂₇

Origin of name: for T. Witt, Swedish mining engineer at the Falun Mine

Crystal system: Monoclinic

Crystal class: 2/m

Twinning:

Unit cell: a = 7.21, b = 4.08, c = 15.5, β = 98.75°

Colour: Light lead-gray

Diaphaneity: Opaque

Luster: Metallic

Habit: massive, resembling molybdenite, striations parallel [010]

Hardness: 2 to 2.5

Specific gravity: 7.12

Cleavage: 1; good

Tenacity: 

Streak: Black

Synonyms/varieties:

Comments: series with cannizarite