Pillaite

Formula: Pb₉Sb₁₀S₂₃ClO_0.5

Origin of name: Named for Leopoldo Pilla (1805-1848), Italian Earth Scientist and hero of Italian independence

Crystal system: Monoclinic

Crystal class: 2/m

Twinning: 

Unit cell: a = 49.65, b = 4.15, c = 21.91, β = 99.76°

Colour: Black

Diaphaneity: Opaque

Luster: Metallic

Habit: Acicular

Hardness: 3-4

Specific gravity: 5.77

Cleavage: None

Tenacity: Brittle, irregular/uneven fracture

Streak: Brownish black

Synonyms/varieties:

Comments: