Galena
Galena, the principal ore of lead. Galena is lead sulfide, a compound of lead and sulfur. It usually occurs in cubic crystals with a lead-gray metallic luster. Some types of galena contain silver. The ore is soluble in nitric acid and in hot hydrochloric acid.
Chemical formula: PbS. Specific gravity: 7.4-7.6. Hardness: 2.5.