Quartzite pebble

Pale gray-white, rounded pebble with a granular, sugary surface and vitreous-to-dull luster. Quartz hardness is 7 Mohs; individual crystals are too small to identify confidently from the image.

Forms when quartz-rich sandstone is recrystallized under heat and pressure, typically during regional metamorphism. Its exact age and source cannot be determined from the image.

Quartzite is used as crushed stone, paving and building material, and sometimes as a decorative stone; this small pebble is mainly suitable for collecting or landscaping.

Quartz grains in true quartzite are tightly fused, so the rock commonly fractures through grains rather than around them.

A light color and hard, quartz-rich, granular texture are consistent with quartzite, but a photograph alone cannot distinguish it reliably from quartz-rich sandstone or another pale pebble. Quartzite occurs worldwide in metamorphic belts and river or beach gravels.