metamorphic

Quartzite Pebble

Metamorphic Quartzite (SiO2)

AI-generated identification · may be incorrect

Hardness: 7 on the Mohs scale; Color: Tan to off-white with yellowish hues; Luster: Vitreous to greasy; Crystal structure: Trigonal (microcrystalline quartz grains fused together); Cleavage: None (fractures conchoidally); Specific gravity: 2.65

Hardness: 7 on the Mohs scale
Color: Tan to off-white with yellowish hues
Luster: Vitreous to greasy

Identified August 3, 2026More metamorphic →

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Physical properties

Formation & geological history

Formed through the metamorphism of quartz-rich sandstone or chert under high heat and tectonic pressure, typically during ancient mountain-building events over millions of years.

Uses & applications

Used in landscaping, decorative stone, construction aggregate, and occasionally as a tumbling or lapidary specimen.

Geological facts

Quartzite is extremely durable and resistant to chemical weathering, which is why quartz-rich rocks often survive as rounded pebbles in riverbeds and beaches long after other 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 knife), lack of cleavage, and sugary texture on freshly broken surfaces. Commonly found in river gravels, glacial tills, and ancient sedimentary formations worldwide.