Galena
Galena (Lead Sulfide) · Mineral Specimen / Industrial Mineral / Metallic Ore
Crystal System
Cubic (Isometric); typically occurs as cubes, octahedrons, or massive granular forms with perfect cubic cleavage.
Mineral Group
Sulfides
Chemical Formula
PbS with common inclusions of Ag (Silver)
Formation Process
Hydrothermal; typically formed in medium to low-temperature hydrothermal veins or through replacement of limestone in sedimentary rocks.
About This Crystal
The specimen exhibits a lead-gray color with a high metallic luster and a granular, somewhat crushed habit. It is opaque with characteristic bright, mirror-like reflections on broken cleavage surfaces.
Physical Characteristics
Color: Lead-gray; Streak: Lead-gray to black; Cleavage: Perfect cubic (three directions at 90 degrees); Fracture: Subconchoidal or uneven; Specific Gravity: 7.2–7.6 (very heavy); Magnetism: None; Non-fluorescent.
Optical Properties
Opaque (not transparent); Isotropic; High metallic reflectivity; exhibits no pleochroism or birefringence.
Hardness & Durability
Origin Region
Major sources include Missouri (USA), Mexico, Peru, and Morocco; found in hydrothermal veins and sedimentary environments.
Hardness & Durability
Mohs Hardness: 2.5–2.75. Very soft and brittle; easily scratched by a copper coin and prone to breaking along cleavage planes.
Care & Maintenance
Clean only with dry cloth or soft brush; avoid water as it may oxidize. Store in a cool, dry place. Wash hands after handling as it contains lead which is toxic if ingested.
Rarity & Value
Very common mineral; value is generally low for massive samples, though well-formed cubic crystals are sought after by collectors. Silver-rich (argentiferous) varieties are valued for ore mining.
Special Characteristics
Silver content often makes it an important ore of silver. Notable for its extreme density (heaviness) relative to its size and its perfect cubic cleavage shards.
Lore & History
Used since ancient times as an ore for lead and silver; Egyptians used it as kohl (eyeliner). In crystal lore, it is believed to be a 'grounding' stone that provides insight into one's past and future.