Felbertalite

Formula: Cu₂Pb₆Bi₈S₁₉

Origin of name: Named for the locality, Felbertal valley, Salzburg Province, Austria

Crystal system: Monoclinic

Crystal class: 2/m

Twinning: 

Unit cell: a = 27.6367, b = 4.0499, c = 20.7409, β = 131.258°

Colour: Gray

Diaphaneity: Opaque

Luster: Metallic

Habit: Granular, subhedral grains in matrix

Hardness: 3.5-4

Specific gravity: 

Cleavage: [001] perfect

Tenacity: Brittle, uneven fracture

Streak: Grayish black

Synonyms/varieties:

Comments:  Forms a homologous series with junoite