Allargentum

Formula:  Ag_1-xSb_x (x = 0.09 to 0.16)

Origin of name:  From Greek for another, and from Latin for silver

Crystal system:  Hexagonal

Crystal class:  6/m 2/m 2/m

Twinning:

Unit cell: a = 2.952 Å, c = 4.773 Å

Colour:  Silver, white

Diaphaneity: Opaque

Luster:  Metallic

Habit:  Massive, in complex intergrowths; small grains

Hardness:  3.5

Specific gravity:  10.0 (synthetic)

Cleavage:  None

Tenacity:

Streak:

Synonyms/varieties: none

Comments: In high-grade Ag-Sb ores