Quartzite with inclusions

Physical Properties

Hardness: 7 on Mohs scale; Color: Gray, tan, and dark bands; Luster: Vitreous to dull; Crystal structure: Trigonal (microcrystalline); Cleavage: None/Conchoidal fracture.

Formation & Geological History

Formed from the metamorphism of quartz sandstone under intense heat and pressure, often during mountain-building events (Orogeny). The dark bands likely represent mineral impurities or organic material from the original sediment.

Uses & Applications

Used in construction as road ballast, decorative stones, flooring, and historically as a material for stone tools due to its hardness and fracture pattern.

Geological Facts

Quartzite is so tough that it often outlasts the surrounding rocks during erosion, often forming the caps of ridges and mountains.

Field Identification & Locations

Identify by its ability to scratch glass and its sugary texture on broken surfaces. This specimen appears river-worn or beach-worn, found commonly in areas with glacial tilt or high-energy water environments.

Identified on: 5/3/2026

Mode: Standard