metamorphic
Weathered quartz-rich rock, possibly iron-stained quartzite
Quartzite (predominantly SiO₂), tentatively; may instead be quartz vein material or chert
AI-generated identification · may be incorrectHardness about 7 Mohs, pale cream to honey-yellow with rusty brown iron-oxide staining, and a dull to sugary/vitreous luster. Massive and granular with no obvious cleavage; quartz-rich material has specific gravity near 2.65.
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Physical properties
Hardness about 7 Mohs, pale cream to honey-yellow with rusty brown iron-oxide staining, and a dull to sugary/vitreous luster. Massive and granular with no obvious cleavage; quartz-rich material has specific gravity near 2.65.
Formation & geological history
Likely formed by metamorphism or cementation of silica-rich sediment, with later weathering producing the yellow-brown staining; exact geological age cannot be determined from the photograph.
Uses & applications
Usually a common field specimen with little commercial value; quartzite is used as crushed aggregate, building stone, and occasionally decorative stone.
Geological facts
The yellow and brown colors commonly reflect limonite or goethite coatings rather than yellow quartz. A steel file should barely scratch fresh quartz-rich surfaces, while glass can be scratched by them.
Field identification & locations
Common in quartz veins, metamorphic terrains, stream gravels, and glacial deposits. Confirm by testing hardness, examining a fresh broken surface, and checking whether grains are fused (quartzite) or waxy/conchoidal (chert).
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