Galena
Galena (Lead Sulfide) · Mineral Specimen / Industrial Mineral (Primary ore of lead)
Crystal System
Cubic (Isometric); typically cubes, octahedrons, or massive granular forms; contact twinning is common.
Mineral Group
Sulfides; Galena group (PbS)
Chemical Formula
PbS (frequently containing trace Silver, Antimony, or Bismuth)
Formation Process
Hydrothermal (low to medium temperature veins), or formed by replacement in limestone/dolomite (Sedimentary/Metamorphic).
About This Crystal
A lead-gray mineral with a distinct bright metallic luster when freshly cleaved. This specimen appears as a granular metallic mass embedded in a reddish-brown iron-stained matrix. It is opaque with a silvery-blue sheen on faceted surfaces.
Physical Characteristics
Lead-gray color; lead-gray to black streak; perfect cubic cleavage in 3 directions; subconchoidal to even fracture; very high specific gravity (7.4–7.6); brittle; non-magnetic; non-fluorescent.
Optical Properties
Opaque; metallic luster; isotropic; high reflectivity (approximately 42% in polished section).
Hardness & Durability
Origin Region
Globally distributed; notable sources include Joplin, Missouri (USA), Cornwall (England), and New South Wales (Australia). Found in hydrothermal veins and sedimentary deposits.
Hardness & Durability
Mohs hardness 2.5–2.75 (can be scratched by a copper coin); low toughness; very brittle; prone to oxidation over time.
Care & Maintenance
Clean with a soft dry brush; avoid water and ultrasonic cleaning. Contains lead: wash hands after handling. Keep away from heat and acids. Store in a dry environment.
Rarity & Value
Relatively common; value is determined by crystal size, symmetry, and silver content. Fine cubic specimens are highly sought by collectors, though the base material is inexpensive.
Special Characteristics
High density (feels unexpectedly heavy for its size); perfect cleavage into smaller cubes; can exhibit a blue-tinted tarnished 'iridescence' under certain conditions.
Lore & History
Historically used as an ingredient for 'kohl' (eye makeup) in Ancient Egypt and as the primary source for smelting lead for thousands of years. In traditional lore, it is considered a 'grounding' stone associated with the Root Chakra, believed to provide stability.