Playfairite

Formula: Pb₁₆Sb₁₈S₄₃

Origin of name: for John Playfair, Scottish geologist

Crystal system: monoclinic

Crystal class: 2/m

Twinning: 

Unit cell: 

Colour: lead-gray to black

Diaphaneity: opaque

Luster: metallic

Habit: crystals tabular, striated parallel to elongation

Hardness: 

Specific gravity: 5.80

Cleavage: 1; {100} perfect

Tenacity: 

Streak: black

Synonyms/varieties:

Comments: known from polished section