Quartzite Breccia

Physical Properties

Hardness: 7 (Mohs scale); Color: White, cream, tan with darker inclusions; Luster: Vitreous to waxy; Structure: Crystalline clasts in a fine-grained matrix; Cleavage: None (conchoidal fracture); Specific Gravity: 2.6-2.7

Formation & Geological History

Formed through the mechanical fracturing of pre-existing quartz-rich rocks (tectonic activity or impact) followed by recrystallization during metamorphism or hydrothermal cementation.

Uses & Applications

Primarily used as aggregate in road construction, landscaping, and high-silica industrial source material. Select pieces are used for lapidary items.

Geological Facts

This specimen shows brecciation, where angular fragments are cemented together. Quartzite is often tougher than its parent sandstone, as it breaks through the quartz grains rather than around them.

Field Identification & Locations

Identify in the field by its extreme hardness (cannot be scratched by a steel knife) and the presence of angular milky quartz fragments welded into a solid mass. Found in areas of significant crustal compression or fault zones.

Identified on: 4/30/2026

Mode: Standard