Zinkenite

Formula: Pb₉Sb₂₂S₄₂

Origin of name: for J.K.L.  Zinken mineralogist (1798-1862)

Crystal system: Hexagonal

Crystal class: 6

Twinning:

Unit cell: a = 22.13 Å, c = 4.318 Å

Colour: Steel-gray, gray, may tarnish iridescent

Diaphaneity: Opaque

Luster: Metallic

Habit: Crystals slender prismatic, striated vertically, radial fibrous to columnar aggregates, massive

Hardness: 3 to 3.5

Specific gravity: 5.12-5.36

Cleavage: 1; {11-20} indistinct

Tenacity: Uneven

Streak: Steel-gray

Synonyms/varieties:

Comments: