metamorphic
Rounded gray pebble, likely quartzite
Quartzite, composed predominantly of quartz (SiO₂)
AI-generated identification · may be incorrectGray to blue-gray, opaque, and dull to slightly glassy; quartz hardness is 7 Mohs, with no cleavage and a granular crystalline texture. The photograph alone cannot confirm the identification; other gray rocks could look similar.
Identified More metamorphic →
Explore Rounded gray pebble, likely quartzite in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Gray to blue-gray, opaque, and dull to slightly glassy; quartz hardness is 7 Mohs, with no cleavage and a granular crystalline texture. The photograph alone cannot confirm the identification; other gray rocks could look similar.
Formation & geological history
Quartzite forms when quartz-rich sandstone is recrystallized by heat and pressure during metamorphism. Its age depends on the source rock and metamorphic event; the pebble’s rounded shape likely reflects transport by water or glacial ice.
Uses & applications
Quartzite is used as aggregate, paving and building stone, and sometimes as decorative material; this small pebble is mainly suitable for collecting or landscaping.
Geological facts
Quartz grains in true quartzite are fused together, so it tends to fracture through grains rather than crumble along grain boundaries.
Field identification & locations
Look for a hard, dense pebble that resists scratching by a steel knife and shows interlocking quartz grains on a fresh break. Quartzite occurs worldwide in river, beach, and glacial deposits; a single image is insufficient for certain identification.
More like this
