Mineral

Gold Ore in Quartz

Auriferous Quartz (Gold: Au; Quartz: SiO2)

Hardness: 7 (Quartz) / 2.5-3 (Gold); Color: Milky white to grey quartz with metallic yellow inclusions and rusty iron staining; Luster: Vitreous quartz with metallic gold; Crystal Structure: Trigonal (Quartz), Cubic (Gold); Cleavage: None.

Hardness: 7 (Quartz) / 2
Luster: Vitreous quartz with metallic gold

Identified March 25, 2026More mineral →

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Physical properties

Formation & geological history

Formed through hydrothermal processes where hot, mineral-rich fluids circulate through fractures in the Earth's crust (veins). This typically occurs in metamorphic belts or near igneous intrusions. Geological age varies from Archean to Cenozoic.

Uses & applications

Primary source for commercial gold extraction; specimens are highly valued by mineral collectors and used in 'specimen gold' jewelry.

Geological facts

Most of the world's gold has been extracted from quartz veins. The 'rusty' appearance (limonite/goethite) is often a 'pathfinder' for prospectors, signaling that sulfides have oxidized and may have left free gold behind.

Field identification & locations

Identify in the field by checking for high specific gravity in the yellow metallic parts and ensuring the gold is malleable (does not shatter when poked with a needle, unlike pyrite). Common in historic mining districts like California (USA), Ontario (Canada), and Western Australia.

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