metamorphic
Quartz-rich metamorphic rock (likely quartzite)
Quartzite, composed predominantly of quartz (SiO₂)
AI-generated identification · may be incorrectPale gray to tan, rough and granular with a faint vitreous sparkle. Quartz has Mohs hardness 7, a trigonal crystal structure, no cleavage, and specific gravity near 2.65; the specimen’s texture is consistent with quartzite but cannot be confirmed from the photo alone.
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Physical properties
Pale gray to tan, rough and granular with a faint vitreous sparkle. Quartz has Mohs hardness 7, a trigonal crystal structure, no cleavage, and specific gravity near 2.65; the specimen’s texture is consistent with quartzite but cannot be confirmed from the photo alone.
Formation & geological history
Forms when quartz sandstone is recrystallized and fused during metamorphism. Its age and formation environment cannot be determined from appearance alone.
Uses & applications
Quartzite is used as building and decorative stone, aggregate, and sometimes as a silica source; this rough piece is mainly suitable for collecting or display.
Geological facts
Quartz grains in true quartzite are tightly intergrown, so the rock typically breaks across grains rather than around them.
Field identification & locations
Check for hardness and grain-boundary fracture: it should scratch glass, and a fresh break should pass through grains. Quartzite occurs worldwide in metamorphic belts; the photo does not establish locality.
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