Galena
Galena (Lead Sulfide) · Mineral Specimen / Industrial Mineral
Crystal System
Cubic (Isometric); commonly occurs in cubic or octahedral habits, and can also be found in massive or granular forms.
Mineral Group
Sulfides
Chemical Formula
PbS
Formation Process
Hydrothermal; typically forms in medium to low-temperature hydrothermal veins or through replacement of limestone and dolostone.
About This Crystal
It has a lead-gray color with a bright metallic luster when fresh, though it can tarnish to a duller gray. It is opaque, and its cubic cleavage is highly distinctive, often showing as small reflective squares within a massive matrix.
Physical Characteristics
Color: Lead-gray; Streak: Lead-gray to black; Luster: Metallic; Cleavage: Perfect cubic; Fracture: Subconchoidal; Specific Gravity: 7.4–7.6 (very heavy); Tenacity: Brittle.
Optical Properties
Isotropic (singly refractive) due to cubic structure; Opaque (does not transmit light); metallic reflectivity is high.
Hardness & Durability
Origin Region
Leadville, Colorado (USA); Joplin, Missouri (USA); Freiberg (Germany); Cornwall (England). Often found in hydrothermal veins and sedimentary deposits.
Hardness & Durability
Mohs hardness: 2.5; low durability and very brittle. It is easily scratched and can crumble into cubes upon impact.
Care & Maintenance
Clean with a dry, soft cloth; avoid acids and prolonged exposure to water which can cause oxidation. Due to lead content, wash hands after handling and keep away from children.
Rarity & Value
Common mineral; value is generally low for massive specimens, but well-formed cubic crystals are sought after by collectors. Industrial value as the primary ore of lead.
Special Characteristics
High specific gravity (unusually heavy for its size); perfect cubic cleavage allows it to break into smaller cubes regardless of specimen size.
Lore & History
Used by Ancient Egyptians as kohl (eye makeup) and has been the primary source of lead for smelting since antiquity. Historically used for radio crystal detectors (cat's whiskers). Traditionally used in grounding practices in crystal lore.