Anyuiite

Formula:  AuPb₂

Origin of name:  Locality; Anyui River, Russia

Crystal system:  Tetragonal

Crystal class:  4/m 2/m 2/m

Twinning:

Unit cell: a = 7.39 Å, c = 5.61 Å

Colour:  Silvery grey

Diaphaneity: Opaque

Luster: Metallic

Habit:  Platy aggregates from 1-50 x 100-900 μm and prismatic crystals 50 x 100 μm in complex intergrowths with native lead

Hardness:  3

Specific gravity:

Cleavage:  None

Tenacity:

Streak: Lead grey

Synonyms/varieties:

Comments:  Oxidizes in 1.5-2 days to dull lead-grey; nonmagnetic