Aleksite

Formula:  PbBi₂Te₂S₂

Origin of name:  After locality; Alekseev mine, Sutamskii region, Russia

Crystal system:  Hexagonal

Crystal class:  2?

Twinning:

Unit cell: a = 4.238 Å, c = 79.76 Å

Colour:  Pale gray with greenish tint in reflected light

Diaphaneity: Opaque

Luster: Metallic

Habit:  Platy grains, microscopic

Hardness: 2 to 2.5

Specific gravity:  7.8 (calculated)

Cleavage: 1; {0001} perfect

Tenacity:

Streak:

Synonyms/varieties: none

Comments: Of hydrothermal origin with galena, gold, altaite, tetradymite, rucklidgeite, quartz