metamorphic
Rounded stream pebbles (likely quartzite and iron-stained sandstone)
Quartzite (SiO₂), with a possible ferruginous sandstone pebble (quartz + iron oxides)
AI-generated identification · may be incorrectThe upper gray, banded pebble appears fine-grained and hard, with subdued luster and no obvious cleavage; likely Mohs 6.5–7. The lower reddish-brown pebble is probably quartz-rich sandstone or weathered quartzite, roughly Mohs 6–7; exact identification requires testing.
Identified More metamorphic →
Explore Rounded stream pebbles (likely quartzite and iron-stained sandstone) in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
The upper gray, banded pebble appears fine-grained and hard, with subdued luster and no obvious cleavage; likely Mohs 6.5–7. The lower reddish-brown pebble is probably quartz-rich sandstone or weathered quartzite, roughly Mohs 6–7; exact identification requires testing.
Formation & geological history
These are naturally water-worn clasts, likely derived from older quartz-rich rocks and transported in a stream or gravel deposit. Their precise geological age cannot be determined from the photograph; the coin provides scale.
Uses & applications
Common pebbles have little commercial value, though attractive quartzite may be used for landscaping, aggregate, lapidary work, or small polished specimens.
Geological facts
The gray stone’s parallel light-dark bands may reflect sedimentary layering or metamorphic fabric, while the brown color commonly results from hematite or limonite staining.
Field identification & locations
Test streak, hardness, and acid reaction: quartzite should not scratch with a steel knife easily and will not fizz in dilute hydrochloric acid. Commonly found in river gravels, beaches, and glacial deposits.
More like this
