metamorphic
Rounded gray metamorphic pebble, likely quartzite or gneiss
Quartzite (quartz-rich rock) or fine-grained gneiss; exact identification requires testing
AI-generated identification · may be incorrectGray-brown, rounded and weathered, with subtle lighter mineral grains and possible foliation. Likely hardness about 6–7 Mohs, vitreous to dull luster, no obvious cleavage, and moderate-to-high specific gravity around 2.6–2.8.
Identified More metamorphic →
Explore Rounded gray metamorphic pebble, likely quartzite or gneiss in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Gray-brown, rounded and weathered, with subtle lighter mineral grains and possible foliation. Likely hardness about 6–7 Mohs, vitreous to dull luster, no obvious cleavage, and moderate-to-high specific gravity around 2.6–2.8.
Formation & geological history
Probably a naturally water-rounded cobble derived from metamorphic bedrock; quartzite forms when sandstone is recrystallized, while gneiss forms under high-grade metamorphism. Its metamorphic age cannot be determined from the photograph.
Uses & applications
Commonly used as landscaping stone, aggregate, and decorative material; attractive pieces may be collected but are generally not gem-grade.
Geological facts
Quartzite resists scratching by steel and commonly breaks across quartz grains rather than around them. Gneiss typically shows visible mineral banding, which is not clearly evident here.
Field identification & locations
Likely found in river gravels, glacial deposits, or eroded metamorphic terrains. Check for glass-scratching hardness, a white quartz streak, and visible foliation; acid testing is usually nonreactive.
More like this
