Galena
Galena · Mineral Specimen / Industrial Mineral (Ore of Lead)
Crystal System
Cubic (Isometric); common habits include cubic, octahedral, and massive or granular aggregates
Mineral Group
Sulfides
Chemical Formula
PbS (Lead Sulfide)
Formation Process
Hydrothermal (low to medium temperature veins) and contact metamorphic deposits, often replacing limestone or dolostone
About This Crystal
Opaque metallic mineral with a distinct lead-gray color. It exhibition a bright metallic luster on fresh surfaces which may tarnish to a dull gray. Often found in cubic crystals or granular masses within a matrix.
Physical Characteristics
Color: Lead gray; Streak: Lead gray; Cleavage: Perfect cubic (three directions at 90 degrees); Fracture: Subconchoidal or uneven; Specific Gravity: 7.2 - 7.6; Non-fluorescent; Brittle tenacity
Optical Properties
Opaque; Metallic luster; No birefringence or pleochroism due to cubic symmetry and opacity; Refractive index is inapplicable
Hardness & Durability
Origin Region
Missouri and Kansas (USA), Peru, Mexico, Bulgaria, and Broken Hill (Australia); forms in hydrothermal veins and sedimentary environments
Hardness & Durability
Mohs hardness: 2.5; low toughness; very brittle; sensitive to impact and pressure
Care & Maintenance
Clean with a soft brush; avoid water as it can promote oxidation; handle with gloves due to lead content; wash hands after handling; store separately from harder minerals
Rarity & Value
Common; value depends on crystal size and perfection; rare habits like hopper crystals or twins command higher prices; generally inexpensive as an industrial ore
Special Characteristics
Significant for being the primary ore of lead and a major source of silver (when argentiferous); distinct high density (heavy feel) for its size
Lore & History
Historically used as a cosmetic (kohl) in Ancient Egypt and as an ore since 3000 BCE; traditionally associated with grounding and centering in lore, though lead toxicity is a primary modern safety concern