Quartzite (with Metamorphic Foliation)

Physical Properties

Hardness: 7 (Mohs scale), Color: Grayish-brown with white quartz veins, Luster: Vitreous to dull, Crystal Structure: Hexagonal (microcrystalline), Cleavage: None (conchoidal fracture)

Formation & Geological History

Formed from the metamorphism of quartz-rich sandstone under intense heat and pressure, often during mountain-building events. This specimen shows river-worn smoothing over a long geological period.

Uses & Applications

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

Geological Facts

Quartzite is so durable that it often survives intense weathering that destroys surrounding rocks, frequently forming the caps of hills and ridges.

Field Identification & Locations

Identify in the field by its inability to be scratched by a steel knife and its grainy, sandpaper-like texture that has been fused into a solid mass. Commonly found in riverbeds or glacial deposits.

Identified on: 4/30/2026

Mode: Standard