mineral
Epithermal Gold Ore (in Quartz/Rhyolite matrix)
Auriferous Quartz (Au + SiO2)
AI-generated identification · may be incorrectHardness: 7 (matrix) to 2.5 (gold); Color: Tan, greenish-grey, or white with metallic yellow inclusions; Luster: Dull to metallic; Crystal Structure: Trigonal/Isometric; Specific Gravity: ~2.65 for matrix.
- Hardness
- 7 (matrix) to 2
- Color
- Tan, greenish-grey, or white with metallic yellow inclusions
- Luster
- Dull to metallic
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Physical properties
Hardness: 7 (matrix) to 2.5 (gold); Color: Tan, greenish-grey, or white with metallic yellow inclusions; Luster: Dull to metallic; Crystal Structure: Trigonal/Isometric; Specific Gravity: ~2.65 for matrix.
Formation & geological history
Formed via hydrothermal activity where mineral-rich hot fluids circulate through volcanic host rocks (rhyolite/andesite) depositing gold and quartz in veins and cavities.
Uses & applications
Primary source for industrial gold production, jewelry making, and investment as bullion; high-grade specimens are kept for mineral collections.
Geological facts
This specimen shows typical 'vuggy' texture where minerals have crystallized in open cavities. Approximately 80% of the world's newly mined gold comes from such hydrothermal deposits.
Field identification & locations
Identify by looking for metallic yellow streaks that do not shatter when poked with a needle (unlike pyrite). Heavy weight for size may indicate high metal content. Found globally in volcanic arcs.
