metamorphic
Weathered quartz-rich metamorphic rock, likely quartzite
Quartzite, predominantly microcrystalline quartz (SiO₂), with iron-oxide staining and dark mica or amphibole inclusions
AI-generated identification · may be incorrectHardness about 7; pale gray-white with yellow-brown iron staining and dark green-gray patches; typically glassy to dull, massive, and nonfoliated, with no obvious cleavage. Dense and resistant, commonly scratches glass.
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Physical properties
Hardness about 7; pale gray-white with yellow-brown iron staining and dark green-gray patches; typically glassy to dull, massive, and nonfoliated, with no obvious cleavage. Dense and resistant, commonly scratches glass.
Formation & geological history
Forms when quartz-rich sandstone is recrystallized under heat and pressure during regional metamorphism; its exact geological age cannot be determined from the image. Iron-bearing fluids commonly produce the yellow-brown weathering colors.
Uses & applications
Used as crushed stone, aggregate, road material, decorative landscaping stone, and sometimes countertops or building facing; attractive specimens have modest collector value.
Geological facts
Quartzite commonly preserves faint original sandstone textures but breaks across fused quartz grains rather than around individual sand grains. The dark patches may represent mica, amphibole, or other accessory minerals.
Field identification & locations
Common in metamorphic mountain belts and glacial or stream gravels; identify by its very hard, quartz-rich texture and sugary fracture, distinguishing it from softer sandstone. A hand lens and hardness test would improve confidence.
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