Quartzite

Physical Properties

Hardness: 7 on Mohs scale; Color: typically white to gray, often with reddish or yellowish tints; Luster: vitreous to dull; Structure: non-foliated, granular; Cleavage: none; SG: 2.6-2.7.

Formation & Geological History

Formed from the regional metamorphism of quartz sandstone under high heat and pressure, causing quartz grains to recrystallize into a dense network of interlocking crystals.

Uses & Applications

Used as a decorative stone in construction, crushed stone for road ballast, and in the manufacturing of glass and ceramics due to high silica content.

Geological Facts

Quartzite is so hard and durable that it often forms the crests of ridges and hills. It can withstand chemical weathering much better than the rocks around it.

Field Identification & Locations

Identify in the field by its sugary texture and extreme hardness (it will easily scratch glass). It breaks through grains rather than around them, unlike sandstone. Common in fold mountain belts.

Identified on: 5/3/2026

Mode: Standard