Galena
Lead Sulfide (Galena) · Mineral Specimen / Industrial Metal Ore
Crystal System
Cubic (Isometric); habit is typically cubic or octahedral, also massive or granular as seen here
Mineral Group
Sulfides (Galena Group)
Chemical Formula
PbS (Lead Sulfide), often containing silver (Ag), zinc (Zn), or antimony (Sb)
Formation Process
Hydrothermal (formed in medium to low-temperature hydrothermal veins and replacement deposits)
About This Crystal
Indicated by a heavy, metallic luster with a lead-gray to bluish-gray color. The specimen shows a metallic sheen on fresh surfaces but can have a dull gray tarnish. Appearance is opaque and dense.
Physical Characteristics
Color: Lead-gray; Streak: Lead-gray; Cleavage: Perfect cubic (three directions at 90 degrees); Fracture: Subconchoidal or uneven; SG: 7.2–7.6 (very heavy); Magnetism: None; Fluorescence: None
Optical Properties
Opaque; Metallic luster; No birefringence or refractive index visible (isotropic)
Hardness & Durability
Origin Region
Global; notable sources include USA (Missouri, Tri-State district), Mexico, Morocco, and various lead-zinc mines
Hardness & Durability
Mohs hardness: 2.5–2.75 (very soft, can be scratched by a copper coin); Brittle tenacity; Requires careful handling to avoid chipping
Care & Maintenance
Wash hands after handling due to lead content; do not ingest; clean with dry cloth; avoid acidic solutions which can dissolve the metallic surface; store separately from hard stones
Rarity & Value
Common; Value is generally low for massive specimens, higher for well-formed cubic crystals or silver-rich (argentiferous) varieties; widely used as the primary ore of lead
Special Characteristics
Notable for extreme density (high specific gravity) relative to its size; exhibits perfect cubic cleavage if broken; often associated with yellow sulfur or brown sphalerite (possibly the brown oxidation visible on the rim)
Lore & History
Historically the most important ore for lead and silver; used in ancient Egypt as kohl (eyeliner); in folklore, it is traditionally associated with grounding and centering energy