metamorphic

Quartzite Pebble

Metamorphic Quartzite

AI-generated identification · may be incorrect

Hardness: 7 on the Mohs scale. Color: White to grey with brownish-gray veins or discoloration. Luster: Vitreous to greasy on fresh surfaces. Crystal structure: Trigonal (microcrystalline quartz grains fused together). Cleavage: None, fractures conchoidally. Specific gravity: 2.65.

Hardness: 7 on the Mohs scale
Color: White to grey with brownish-gray veins or discoloration
Luster: Vitreous to greasy on fresh surfaces

Identified July 31, 2026More metamorphic →

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Physical properties

Formation & geological history

Formed from quartz-rich sandstone or chert that has been subjected to heat and pressure through regional or contact metamorphism, causing the quartz grains to recrystallize and interlock tightly.

Uses & applications

Used in landscaping, decorative stone, construction aggregate, and occasionally for carving or as polished pocket stones.

Geological facts

Quartzite is extremely durable and weather-resistant, which is why quartz-rich rocks often survive as smooth, rounded pebbles in rivers and beaches long after less durable minerals have eroded away.

Field identification & locations

Can be identified in the field by its high hardness (it will easily scratch glass and cannot be scratched by a steel knife) and the sugary, interlocking crystalline texture visible under a hand lens. Found globally in ancient metamorphic terrains and riverbeds.