mineral
Weathered quartz-rich rock, possibly gold-bearing quartz
Milky quartz with iron-oxide staining; exact host rock is uncertain from the image
AI-generated identification · may be incorrectHardness about 7 Mohs, vitreous to dull luster, white-gray translucent quartz with yellow-brown limonite staining and rounded weathering. Quartz has a trigonal crystal structure and lacks cleavage, showing irregular fracture; visible gold cannot be confirmed visually.
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Physical properties
Hardness about 7 Mohs, vitreous to dull luster, white-gray translucent quartz with yellow-brown limonite staining and rounded weathering. Quartz has a trigonal crystal structure and lacks cleavage, showing irregular fracture; visible gold cannot be confirmed visually.
Formation & geological history
Quartz commonly forms in hydrothermal veins that crystallized as hot, silica-rich fluids cooled in fractures, often during Precambrian to Phanerozoic tectonic activity. Surface weathering rounds the specimen and oxidizes iron-bearing minerals.
Uses & applications
Quartz is used in glass, ceramics, abrasives, electronics, and ornamental stone; attractive pieces are collected. Gold-bearing quartz can have value if assay confirms gold.
Geological facts
Yellow-brown coloration is typically limonite/goethite rather than native gold, which is metallic yellow and malleable. A streak, hardness, density, and assay test are needed for reliable identification.
Field identification & locations
Common in hydrothermal vein districts worldwide, including California, Colorado, Australia, Brazil, and Canada. It scratches ordinary glass, does not scratch easily with a steel knife, and leaves a white streak; professional assay is required to assess gold content.
