Galena
Galena (Lead Sulfide) · Mineral Specimen / Industrial Mineral (Primary ore of Lead)
Crystal System
Cubic (Isometric); typically occurs as cubes, octahedrons, or massive granular forms
Mineral Group
Sulfides; Galena Group
Chemical Formula
PbS (Lead Sulfide), often containing silver (Ag), zinc (Zn), or antimony (Sb)
Formation Process
Hydrothermal; crystalline precipitation in medium-to-low temperature hydrothermal veins or replacement deposits
About This Crystal
A heavy, lead-gray mineral with a distinct metallic luster. This specimen shows a massive granular texture with thousands of tiny cleavage faces.
Physical Characteristics
Color: Lead-gray; Streak: Lead-gray to black; Cleavage: Perfect cubic in 3 directions; Fracture: Subconchoidal; Specific Gravity: 7.2-7.6 (very heavy); Luster: Bright metallic
Optical Properties
Opaque; metallic; non-transparent even in thin sections; high reflectivity but no birefringence or pleochroism due to cubic symmetry
Hardness & Durability
Origin Region
Missouri (USA), Morocco, Bulgaria, and Peru; found in hydrothermal veins and sedimentary environments
Hardness & Durability
Mohs Hardness: 2.5; brittle toughness; low durability for jewelry; can be scratched by a copper coin
Care & Maintenance
Handle with gloves as it contains lead; wash hands after touching; avoid acids; store in a dry environment to prevent oxidation
Rarity & Value
Very common; value depends on crystal size and associations with minerals like Fluorite or Quartz; generally affordable for collectors
Special Characteristics
Natural semiconductor; high density/heaviness; can show 'silver enrichment' appearing brighter; perfect 90-degree cleavage fragments
Lore & History
Historically used as 'Kohl' eyeliner in Ancient Egypt and as the primary source of lead for Roman plumbing; used in early crystal radio detectors