mineral

Epithermal Gold Ore (in Quartz/Rhyolite matrix)

Auriferous Quartz (Au + SiO2)

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.

Hardness: 7 (matrix) to 2
Color: Tan, greenish-grey, or white with metallic yellow inclusions
Luster: Dull to metallic

Identified June 17, 2026More mineral →

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Physical properties

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.

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