metamorphic

Quartzite

Metamorphosed Quartz Sandstone (SiO2)

AI-generated identification · may be incorrect

Hardness: 7 on Mohs scale; Color: light tan/beige/pinkish; Luster: Vitreous to dull; Crystal structure: Trigonal/Hexagonal (microcrystalline); Cleavage: None (conchoidal fracture); Specific gravity: 2.63 - 2.65

Hardness: 7 on Mohs scale
Color: light tan/beige/pinkish
Luster: Vitreous to dull

Identified May 14, 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 (orogeny). Individual quartz grains recrystallize into an interlocking mosaic.

Uses & applications

Used in construction as crushed stone for road ballast, as a decorative building stone, and historically for stone tools due to its hardness and durability.

Geological facts

Quartzite is so tough that it often outlasts the surrounding rocks in a landscape, forming prominent ridges and hills. It is often confused with marble but can be distinguished because quartzite will scratch glass and marble will not.

Field identification & locations

Identify in the field by its extreme hardness (cannot be scratched by a steel nail) and its grainy, sugary texture. It typically feels much denser and harder than common sandstone.