1) Lead mineral 
Baumhauerite (Pb3As4S9) is a rare lead sulfosalt mineral. It crystallizes in the triclinic system, is gray-black to blue-gray and its lustre is metallic to dull. Baumhauerite has a hardness of 3. Baumhauerite occurs as small crystals embedded in dolomitic marble. It is found primarily in the Lengenbach Quarry, Binnental, in the Valais region of Sw...