Quartzite with inclusions

Physical Properties

Hardness: 7 on Mohs scale; Color: White to grey with dark mineral streaks; Luster: Vitreous to dull; Crystal structure: Non-foliated, granular; Cleavage: None; Specific gravity: approx 2.65

Formation & Geological History

Formed from the metamorphism of quartz sandstone under high heat and pressure. This specific rounded specimen has been weathered and smoothed by water action in a river or coastal environment.

Uses & Applications

Common varieties are used in construction as crushed stone, road ballast, and in the production of glass and ceramics. Polished river stones are used in landscaping.

Geological Facts

Quartzite is so tough that it often outlasts the mountain ranges it was part of. If you break it, the fracture will go through the individual quartz grains rather than around them, which distinguishes it from sandstone.

Field Identification & Locations

Identify in the field by its extreme hardness (cannot be scratched by a steel blade) and its granular, sugary texture. Look for it in glaciated areas or riverbeds where resilient rocks accumulate.

Identified on: 4/20/2026

Mode: Standard