metamorphic

Quartzite Pebble

Quartzite (SiO2)

AI-generated identification · may be incorrect

Hardness: 7 on Mohs scale; Color: light gray to white; Luster: vitreous to dull; Crystal structure: hexagonal (trigonal); Grainy, sand-like texture with smooth water-worn surface; Specific gravity: 2.6-2.7.

Hardness: 7 on Mohs scale
Color: light gray to white
Luster: vitreous to dull

Identified June 21, 2026More metamorphic →

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Physical properties

Formation & geological history

Formed when quartz-rich sandstone is subjected to heat, pressure, and chemical activity of metamorphism. This specific specimen has been further shaped by river or coastal erosion (rounding) during the Quaternary period.

Uses & applications

Used as decorative garden stone, in construction aggregates, and historically as a tool stone due to its extreme hardness and durability.

Geological facts

Quartzite is so hard that it will scratch glass and even high-quality steel. It is more resistant to weathering than the sandstone from which it originated.

Field identification & locations

Identified in the field by its hardness (cannot be scratched by a knife) and its grainy 'sugary' appearance under a lens. Common in glacial till and riverbeds worldwide.