igneous
Rounded quartz-rich pebble
Likely quartzite, composed chiefly of SiO₂ (quartz); identification is uncertain from the photograph
AI-generated identification · may be incorrectPale gray-white, rounded and weathered, with a granular/sugary surface and slight sparkle. Quartz hardness is 7 Mohs, vitreous luster, and trigonal crystal structure; quartzite has no cleavage and typically breaks irregularly.
Identified More igneous →
Explore Rounded quartz-rich pebble in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Pale gray-white, rounded and weathered, with a granular/sugary surface and slight sparkle. Quartz hardness is 7 Mohs, vitreous luster, and trigonal crystal structure; quartzite has no cleavage and typically breaks irregularly.
Formation & geological history
If quartzite, it formed when quartz sandstone was metamorphosed under heat and pressure, then was rounded by water or other erosion. Its age and source cannot be determined from the image.
Uses & applications
Small pebbles are commonly used for collecting, landscaping, and decorative crafts; quartzite is also used as construction aggregate and dimension stone.
Geological facts
Quartzite’s interlocking quartz grains make it hard and resistant to weathering. A simple scratch test against glass can help distinguish it from softer rocks, though it is not conclusive.
Field identification & locations
Look for a hard, quartz-rich texture and grains that appear fused rather than loosely cemented; rounded pebbles occur in riverbeds, beaches, and glacial deposits worldwide.
