metamorphic
Quartz-rich metamorphic rock, likely quartzite
Quartzite; predominantly microcrystalline quartz (SiO₂), possibly with feldspar or mica impurities
AI-generated identification · may be incorrectTypically very hard (Mohs 7), gray-white, granular, and vitreous to dull; the specimen appears strongly weathered and may show sugary quartz grains but no diagnostic cleavage.
Identified More metamorphic →
Explore Quartz-rich metamorphic rock, likely quartzite in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Typically very hard (Mohs 7), gray-white, granular, and vitreous to dull; the specimen appears strongly weathered and may show sugary quartz grains but no diagnostic cleavage.
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 photograph; quartzites occur in rocks ranging from Precambrian to recent metamorphic belts.
Uses & applications
Used as crushed stone, road aggregate, building stone, countertops, and decorative material; this small, ordinary specimen has little jewelry value.
Geological facts
Quartzite is generally harder and more resistant to weathering than its sandstone precursor, commonly producing durable ridges and resistant stream pebbles.
Field identification & locations
A likely identification if it scratches glass and shows fused, interlocking quartz grains; unlike sandstone, individual grains are difficult to loosen. Common in metamorphic mountain regions and gravel deposits; confirmation requires hardness, acid, and thin-section tests.
More like this
