sedimentary

Gold-Bearing River Sand

Auriferous Placer Sand (Au + various minerals like SiO2 and Fe3O4)

Texture: Granular/Sandy; Hardness: 2.5-3 (Gold) vs 7 (Quartz); Color: Earthy brown with metallic yellow flecks; Luster: Sub-metallic to Vitreous (background) with Metallic flakes; Cleavage: None; S.G.: 19.3 (Gold) vs 2.65 (Sand).

Hardness: 2
Color: Earthy brown with metallic yellow flecks
Luster: Sub-metallic to Vitreous (background) with Metallic flakes

Identified March 5, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the mechanical weathering of gold-bearing quartz veins in mountains. The heavy gold particles are concentrated in riverbeds and stream basins by hydraulic action over thousands of years (Holocene or older).

Uses & applications

Used primarily for gold extraction/refining. The raw sand is often sold to amateur prospectors ('paydirt') for panning practice or hobbyist collection.

Geological facts

This type of deposit is known as a 'placer deposit.' Historically, these deposits sparked the 1849 California Gold Rush and the Klondike Gold Rush because they allow for surface mining with simple tools.

Field identification & locations

Identify in the field by searching inside bends of rivers, behind large boulders, or in 'pockets' of bedrock. Look for 'black sand' (magnetite) which often accompanies gold due to similar high density.

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