Baumhauerite Locality: Lengenbach Quarry , Im Feld (Imfeld; Feld; Fäld), Binn Valley, Wallis (Valais) , Switzerland ( Locality at mindat.org ) Size: 2.0 x 1.7 x 1.0 cm. A large single crystal of this rare lead arsenic sulfide, from the type locality. Ex. Carlton Davis Collection. — Photo: Robert M. Lavinsky · CC BY-SA 3.0
Baumhauerite
A rare gray-black lead-arsenic sulfosalt with a metallic luster and a Mohs hardness of about 3.
Intro adapted from Wikipedia (CC BY-SA).
Baumhauerite is an IMA-recognized mineral species in the sulfosalt class, with the chemical formula Pb₁₂As₁₆S₃₆.
It crystallizes in the triclinic crystal system (space group P-1). It is a member of the Sartorite structural group.
Key properties: Mohs hardness 3; specific gravity 5.33–5.44; Chocolate-brown streak; Metallic. Anisotropism: Strong, dark brown, pale brown, pale brownish gray; may be colorful in green, violet luster.
IMA symbol Bha, grandfathered status — known before the IMA’s founding, named in 1902.
Found in sugary dolostone (Binntal, Switzerland).
It is found associated with With baumhauerite-2a, other lead sulfarsenides, realgar, pyrite, dolomite (Binntal, Switzerland).
The name refers to Professor Heinrich Adolph Baumhauer (1848–1926), German mineralogist, University of Fribourg, Switzerland.