Quartzite Pebble (River Rock)

Hardness: 7 (Mohs scale), Color: yellowish-tan/translucent, Luster: Vitreous to waxy, Crystal structure: Trigonal/Microcrystalline, Specific gravity: 2.65

Formed from the metamorphism of quartz-rich sandstone under intense heat and pressure. This specimen has been smoothed and rounded by hydraulic action in a river or stream environment.

Used in landscaping, construction aggregates, glass making, and as decorative river stones.

Quartzite is so hard that it will scratch glass and steel. It is one of the most durable rocks on the Earth's surface and is often found as river cobbles because it resists erosion better than surrounding minerals.

Identify in the field by its hardness and lack of reaction to acid. It often appears sugary or grainy inside but smooth on the outside when water-worn. Common in areas with ancient sedimentary basins.