Formula: Pb₅Sb₄S₁₁

Species:

Colour: Lead grey

Lustre: Metallic

Hardness: 2½ – 3

Specific Gravity: 6.2

Crystal System: Monoclinic

Name: Named in 1837 by Moritz Christian Julius Thaulow in honor of Charles Louis Boulanger (1810-1849), a French mining engineer. Boulanger first analyzed his namesake species calling it “plomb antimonie sulfure” in 1835.

Type Locality: Molières-Cavaillac, Le Vigan, Gard, Occitanie, France

Easily confused with jamesonite. Homeotype of lopatkaite. May occur in intergrowths with jamesonite and meneghinite. There are interconnected SbS3 groups in the structure as, e.g., in jamesonite, robinsonite, and zinkenite.