Quartzite

Physical Properties

Hardness: 7 on Mohs scale; Color: typically white, gray, or yellowish; Luster: vitreous to dull; Crystal structure: Trigonal (granular texture); Cleavage: none; Specific gravity: 2.6-2.7

Formation & Geological History

Formed through the regional metamorphism of quartz-rich sandstone, where high heat and pressure cause the sand grains to recrystallize and fuse together. Found in many Precambrian to Paleozoic aged mountain belts.

Uses & Applications

Widely used for construction aggregate, decorative stone in flooring and countertops, making glass, and as architectural stone.

Geological Facts

Quartzite is significantly harder and more durable than its parent rock, sandstone. It is so tough that it often forms the crests of mountain ridges because it resists erosion more effectively than surrounding rocks.

Field Identification & Locations

Identify by its sugary or granular texture and its inability to be scratched by a steel nail. Unlike marble, it will not fizz when exposed to acid. Commonly found in metamorphic mountain ranges.

Identified on: 5/5/2026

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