metamorphic

Quartzite

Quartzite (predominantly SiO2)

AI-generated identification · may be incorrect

Hardness: 7 on Mohs scale; Color: yellow, orange, or reddish due to iron oxides; Luster: Vitreous to dull; Structure: Granular, non-foliated; Cleavage: None

Hardness: 7 on Mohs scale
Color: yellow, orange, or reddish due to iron oxides
Luster: Vitreous to dull

Identified July 14, 2026More metamorphic →

Explore Quartzite in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Hardness: 7 on Mohs scale; Color: yellow, orange, or reddish due to iron oxides; Luster: Vitreous to dull; Structure: Granular, non-foliated; Cleavage: None

Formation & geological history

Formed through the metamorphism of quartz sandstone under high heat and pressure, causing the original quartz grains to recrystallize and fuse together into a dense, hard rock.

Uses & applications

Used as a decorative stone in landscaping, as crushed stone for road construction, and historically for making stone tools due to its hardness and conchoidal fracturing.

Geological facts

Quartzite is so hard and chemically resistant that it often forms the caps of hills and ridges because it resists erosion much better than surrounding rocks.

Field identification & locations

Identify in the field by its hardness (it can scratch glass) and its grainy, sugary texture. Unlike sandstone, it will break across the grains rather than around them.