Galena

Physical Properties

Hardness: 2.5-2.75 Mohs; Color: Lead-gray to silvery; Luster: Metallic; Crystal Structure: Isometric (cubic); Cleavage: Perfect cubic in three directions; Specific Gravity: 7.2-7.6 (very heavy)

Formation & Geological History

Formed in hydrothermal veins, contact metamorphic deposits, and as replacements in limestone or dolomite. It is the primary ore of lead and often contains silver inclusions.

Uses & Applications

Primary source of lead for batteries, radiation shielding, and ammunition. Historically used for cosmetics (kohl) and as a semiconductor in early crystal radio receivers. Also used for silver extraction if the specimen is argentiferous.

Geological Facts

Galena is one of the most abundant and widely distributed sulfide minerals. Crystals can form perfect cubes or octahedrons. It was the subject of the very first semiconductor experiments due to its rectifying properties.

Field Identification & Locations

Identify by its high density (unusually heavy for its size), bright metallic luster, and perfect cubic cleavage that causes it to break into smaller cubes. Found globally, with notable deposits in the USA (Missouri), UK, and Morocco.

Identified on: 4/20/2026

Mode: Standard