metamorphic
Rounded quartz-rich pebble (likely quartzite)
Quartzite; predominantly microcrystalline quartz (SiO₂), with possible iron-oxide staining and minor feldspar or mica
AI-generated identification · may be incorrectHardness about 7 Mohs; pale gray, cream, and yellow-orange surface, with a dull to weakly vitreous luster and no visible cleavage. Dense, fine-grained, and smoothly water-rounded; exact identification is limited by the small image.
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Physical properties
Hardness about 7 Mohs; pale gray, cream, and yellow-orange surface, with a dull to weakly vitreous luster and no visible cleavage. Dense, fine-grained, and smoothly water-rounded; exact identification is limited by the small image.
Formation & geological history
Quartzite forms when quartz-rich sandstone is recrystallized during metamorphism, commonly during mountain-building; its precise age cannot be determined visually. The specimen was likely transported and rounded by a stream, beach, or glacial process.
Uses & applications
Quartzite is used as crushed stone, aggregate, paving, and building/ornamental stone; attractive pieces may be used as lapidary material. This small ordinary pebble has little commercial value.
Geological facts
Its quartz content makes it resistant to weathering and typically harder than the surrounding rocks. Yellow-orange coloration commonly comes from iron oxides such as limonite or goethite.
Field identification & locations
Scratch-testing glass or steel should be possible, while a knife generally will not scratch it; a streak test is usually white. Common in metamorphic terrains and river or beach gravels worldwide; a fresh broken surface would better reveal quartz grains and confirm quartzite.
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