metamorphic
Tumbled quartz-rich pebble (likely quartzite)
Quartzite, predominantly SiO₂
AI-generated identification · may be incorrectCream to pale yellow, smoothly rounded and matte-to-waxy; hardness about 7 Mohs, vitreous when freshly broken, with no obvious cleavage and quartz’s hexagonal crystal structure. Its granular texture suggests recrystallized quartz rather than a single crystal.
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Physical properties
Cream to pale yellow, smoothly rounded and matte-to-waxy; hardness about 7 Mohs, vitreous when freshly broken, with no obvious cleavage and quartz’s hexagonal crystal structure. Its granular texture suggests recrystallized quartz rather than a single crystal.
Formation & geological history
Likely a naturally weathered or tumbled quartzite pebble formed when quartz sandstone was metamorphosed under heat and pressure, generally during ancient mountain-building events. The exact geological age and locality cannot be determined from the photograph.
Uses & applications
Used as landscaping gravel, decorative stone, aggregate, and inexpensive tumbled specimens; it has little jewelry value unless unusually colorful or patterned.
Geological facts
Quartzite is highly resistant to weathering and commonly survives as rounded stream gravel. The faint internal banding or seam may reflect original sandstone bedding or a healed fracture.
Field identification & locations
Identify by its very high hardness, granular quartz appearance, lack of fizz in dilute acid, and inability to scratch it with a steel knife; a glass tile can be scratched by quartz. Common worldwide, especially in mountain belts and former sandstone regions.
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