Heteromorphite

Formula:  Pb₇Sb₈S₁₉

Origin of name:  From Greek for other and form

Crystal system:  Monoclinic

Crystal class:  2/m

Twinning: 

Unit cell: 

Colour:  Black

Diaphaneity:  Opaque

Luster:  Metallic

Habit:  Crystals pyramidal, somewhat elongated, distorted, striated, rounded

Hardness:  2.5 to 3

Specific gravity:  5.73

Cleavage:  1; {112} good

Tenacity: 

Streak:  Black

Synonyms/varieties:

Comments: