metamorphic

Quartzite

Quartzite (primarily SiO2)

AI-generated identification · may be incorrect

Hardness: 7 on Mohs scale; Color: Grayish-white with hints of green and tan; Luster: Vitreous to dull; Structure: Granular, non-foliated; Cleavage: None; Specific Gravity: 2.6-2.7

Hardness: 7 on Mohs scale
Color: Grayish-white with hints of green and tan
Luster: Vitreous to dull

Identified July 18, 2026More metamorphic →

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Physical properties

Hardness: 7 on Mohs scale; Color: Grayish-white with hints of green and tan; Luster: Vitreous to dull; Structure: Granular, non-foliated; Cleavage: None; Specific Gravity: 2.6-2.7

Formation & geological history

Formed through the metamorphism of quartz-rich sandstone under heat and pressure, causing the original quartz grains to recrystallize into an interlocking mosaic of crystals.

Uses & applications

Used in construction for road ballast, floor tiles, and countertop surfaces. Also used as a decorative stone and in the manufacturing of silica bricks.

Geological facts

Quartzite is so tough that it often survives weathering better than the rocks around it, creating prominent ridges or hills. It is harder than steel and will easily scratch glass.

Field identification & locations

Identify in the field by its extreme hardness and its sugary, granular texture. Unlike marble, it will not react with acid. Commonly found in folded mountain belts globally.