metamorphic

Quartzite Pebble

Metamorphosed Quartz Sandstone (SiO2)

AI-generated identification · may be incorrect

Hardness: 7 on Mohs scale; Color: White to light tan; Luster: Vitreous to dull; Crystal structure: Trigonal/Hexagonal (microcrystalline); Specific gravity: 2.6-2.7

Hardness: 7 on Mohs scale
Color: White to light tan
Luster: Vitreous to dull

Identified July 15, 2026More metamorphic →

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Physical properties

Hardness: 7 on Mohs scale; Color: White to light tan; Luster: Vitreous to dull; Crystal structure: Trigonal/Hexagonal (microcrystalline); Specific gravity: 2.6-2.7

Formation & geological history

Formed through the metamorphism of quartz-rich sandstone under intense heat and pressure. This specimen shows significant rounding and smoothing due to fluvial (river) or coastal water erosion.

Uses & applications

Used in construction as road ballast, in glass manufacturing if pure enough, for decorative landscaping, and as a durable abrasive.

Geological facts

Quartzite is so tough that it often outlasts the surrounding rock in weathering processes. This specific specimen is a 'river rock' or 'beach pebble,' representing the final stage of mechanical weathering.

Field identification & locations

Identify in the field by its inability to be scratched by a steel knife and its lack of reaction to acid. It is commonly found in riverbeds, glacial tills, and along coastlines globally.