Galena
Galena (Lead Sulfide) · Mineral Specimen and Opaque Ore Mineral
Crystal System
Cubic (Isometric); commonly occurs as cubes, octahedrons, or granular massive forms
Mineral Group
Sulfides; Galena group member
Chemical Formula
PbS (Lead Sulfide), often containing silver (Ag), zinc (Zn), or antimony (Sb)
Formation Process
Hydrothermal; forms in veins under medium to low-temperature environments within hydrothermal vents or through replacement in carbonate rocks.
About This Crystal
Opaque mineral with a brilliant metallic luster and a lead-gray color. Specimens often show cubic cleavage or granular clusters on a matrix of rock or other minerals like quartz.
Physical Characteristics
Color: Lead-gray; Streak: Lead-gray; Cleavage: Perfect cubic (3 planes at 90 degrees); Fracture: Subconchoidal or uneven; Specific Gravity: 7.2-7.6 (very heavy/dense); Brilliance: High metallic luster; Non-fluorescent.
Optical Properties
Opaque (does not transmit light); metallic reflectivity is high; isotropic due to cubic structure but often too opaque for standard RI measurement.
Hardness & Durability
Origin Region
United States (Missouri/Tri-State district), Mexico, Morocco, Germany, and Peru. Formed in hydrothermal veins and sedimentary deposits.
Hardness & Durability
Mohs hardness: 2.5 (soft, easily scratched); Brittle tenacity; high density makes it feel surprisingly heavy for its size.
Care & Maintenance
Clean only with dry cloth or gentle water rinse; avoid ultrasonics. Wash hands after handling due to lead content. Keep away from acids.
Rarity & Value
Very common as a mineral specimen; value is based on crystal size, cubic perfection, and luster. Generally inexpensive unless paired with rare minerals.
Special Characteristics
Exceptional cubic cleavage; high density; primary ore of lead and often a significant source of silver; known for its high metallic sheen.
Lore & History
Historically used as a source of lead and silver since ancient Egypt and Rome. In lore, it is considered a grounding stone that provides insight and facilitates transformation.