Native Gold in Gossan
Native Gold in Limonite-rich Gossan matrix · Collector Mineral Specimen / Precious Metal Ore
Crystal System
Isometric (Cubic) for Gold; the matrix is often Amorphous or Microcrystalline such as massive or earthy habits.
Mineral Group
Native Elements (Gold) and Oxides/Hydroxides (Matrix)
Chemical Formula
Au (Native element) within a matrix typically composed of FeO(OH)·nH2O (Limonite) and Fe2O3 (Hematite)
Formation Process
Supergene enrichment: Gold is concentrated when primary sulfide ore bodies undergo oxidation and weathering near the surface, forming a 'gossan' or iron cap.
About This Crystal
The specimen is a dark, earthy, and iron-rich rock (gossan) featuring a prominent, bright yellow metallic inclusion of native gold. The matrix is opaque with a dull, sub-metallic to earthy luster, while the gold displays a high metallic luster and characteristic yellow hue.
Physical Characteristics
Gold Color: Golden yellow; Streak: Yellow; Cleavage: None; Fracture: Hackly (Gold), Uneven (Matrix); Specific Gravity: ~19.3 for pure gold; Fluorescence: None under UV light.
Optical Properties
Gold is Opaque and isotropic; it exhibits high metallic reflectivity. The iron-rich matrix is also opaque with no significant optical phenomena like birefringence or pleochroism.
Hardness & Durability
Origin Region
Global distribution; notable for historical sites like the Witwatersrand (South Africa), Goldfields-Esperance (Western Australia), and Mother Lode (California, USA).
Hardness & Durability
Gold Mohs Hardness: 2.5 - 3 (very soft and malleable). Matrix Hardness: Variable (4-6). Stability: Gold is chemically inert but physically soft; avoid scratching.
Care & Maintenance
Clean only with warm soapy water. Do not use ultrasonic cleaners or harsh acids which may react with the matrix minerals. Store separately to prevent the soft gold from being scratched by harder stones.
Rarity & Value
The rarity is high when gold is clearly visible in its host matrix. Value is determined by the weight of the gold, the aesthetic of the specimen, and the locality. Generally more valuable as a mineral specimen than as raw melt.
Special Characteristics
Contains native precious metal; displays malleability and extreme density. The 'golden' color is diagnostic. Small wire-like or dendritic growth patterns can sometimes be seen in the gold section.
Lore & History
Gold has been the universal symbol of wealth, power, and the sun across almost every human civilization. Historically, gossans were used by prospectors as 'iron hats' to indicate rich mineral deposits beneath the surface. In lore, it represents abundance and vitality.