metamorphic
Quartz-rich metamorphic rock, likely quartzite
Quartzite; predominantly crystalline SiO₂, with possible iron-oxide and dark mica/mineral inclusions
AI-generated identification · may be incorrectHardness about 7 Mohs; coarse, granular texture with white to cream quartz, dark brown-black patches, and earthy iron staining. Vitreous to dull luster; quartz has no cleavage and irregular fracture. Exact identification is limited by the photograph.
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Physical properties
Hardness about 7 Mohs; coarse, granular texture with white to cream quartz, dark brown-black patches, and earthy iron staining. Vitreous to dull luster; quartz has no cleavage and irregular fracture. Exact identification is limited by the photograph.
Formation & geological history
Forms when quartz-rich sandstone is intensely metamorphosed and recrystallized, commonly during mountain-building; ages vary widely from Precambrian to younger Paleozoic or Mesozoic rocks. Dark areas may represent mica, amphibole, magnetite, or weathering products.
Uses & applications
Used as durable crushed stone, aggregate, paving and building material; attractive pieces are collected or used decoratively, though this specimen appears ordinary.
Geological facts
Quartzite commonly preserves a sugary, interlocking quartz texture and is harder than its parent sandstone. A steel file generally struggles to scratch fresh quartz-rich surfaces.
Field identification & locations
Look for quartz grains fused across broken surfaces, strong resistance to scratching, and little layering or porosity; common in metamorphic mountain belts worldwide. Value is typically $2–$15 for an ordinary hand specimen, or $20–$50 if unusually aesthetic or locality-labeled.
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