Altaite

Formula:  PbTe

Origin of name:  Locality; Altai Mountains, Siberia, Russia

Crystal system:  Cubic

Crystal class:  4/m -3 2/m

Twinning:

Unit cell:  a = 6.443 Å

Colour:  Tin-white with yellowish tint

Diaphaneity: Opaque

Luster:  Metallic

Habit:  Crystals rare, cubic or octahedral; commonly massive

Hardness:  2 to 3

Specific gravity:  8.15 to 8.19

Cleavage:  1; {001} perfect

Tenacity:  Brittle to sectile

Streak: Black

Synonyms/varieties:

Comments:  Series with clausthalite and with galena. In hydrothermal vein gold deposits