metamorphic

Quartzite Pebble

Metamorphosed Quartz Sandstone (SiO2)

AI-generated identification · may be incorrect

Hardness: 7 on Mohs scale; Color: Tan, beige, or white; Luster: Vitreous to dull; Crystal structure: Trigonal/Hexagonal (microcrystalline); Cleavage: None (conchoidal fracture); Specific gravity: 2.6-2.7

Hardness: 7 on Mohs scale
Color: Tan, beige, or white
Luster: Vitreous to dull

Identified May 21, 2026More metamorphic →

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Physical properties

Formation & geological history

Formed through the metamorphism of quartz-rich sandstone under intense heat and pressure, typically during mountain-building events. These pebbles are often rounded by fluvial or glacial transport.

Uses & applications

Used primarily as construction aggregate, decorative landscaping stone, and in some industrial glass manufacturing when pure.

Geological facts

Quartzite is so tough that it often outlasts the surrounding rocks during erosion, leading to the formation of rounded high-silica pebbles found in riverbeds and on beaches.

Field identification & locations

Identify by its hardness (it will easily scratch glass) and its granular, sugary texture. It is extremely common in glaciated regions and river valleys globally.