Rock Identifier
Gold Ore (in Quartz/Gossan matrix) (Native Gold (Au) in Limonite/Quartz matrix) — mineral
mineral

Gold Ore (in Quartz/Gossan matrix)

Native Gold (Au) in Limonite/Quartz matrix

Hardness: 2.5-3 (Gold) / 7 (Quartz); Color: Metallic yellow in a rusty brown/grey matrix; Luster: Metallic; Crystal Structure: Isometric; Specific Gravity: 19.3 (pure gold)

Hardness
2
Color
Metallic yellow in a rusty brown/grey matrix
Luster
Metallic
Identified More mineral

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Physical properties

Hardness: 2.5-3 (Gold) / 7 (Quartz); Color: Metallic yellow in a rusty brown/grey matrix; Luster: Metallic; Crystal Structure: Isometric; Specific Gravity: 19.3 (pure gold)

Formation & geological history

Formed via hydrothermal veins where hot, mineral-rich fluids deposit gold in quartz fissures, or through secondary enrichment in gossans (weathered tops of ore deposits).

Uses & applications

Primary source for gold extraction used in jewelry, electronics, investment bullion, and dentistry.

Geological facts

Most gold found in nature is actually alloyed with small amounts of silver. The 'rusty' appearance of the host rock often indicates the presence of decomposed iron sulfides like pyrite, which may have originally contained gold.

Field identification & locations

Identify by looking for metallic yellow specks that do not crumble when poked with a needle (unlike brittle pyrite or mica). Common in gold-bearing regions like Australia, Nevada (USA), and South Africa.