Quartzite River Rock

Physical Properties

Hardness: 7 (Mohs scale); Color: Tan, rusty brown, or orange-red due to iron oxide staining; Luster: Dull to waxy; Texture: Granular, sugary texture when broken; Cleavage: None (conchoidal fracture).

Formation & Geological History

Formed from the metamorphism of quartz-rich sandstone under intense heat and pressure. These specific specimens are water-worn, having been tumbled and rounded in a river or fluvial environment over thousands of years.

Uses & Applications

Used primarily in landscaping, decorative ground cover, construction aggregate, and as 'river stone' for architectural accents.

Geological Facts

Quartzite is so hard that it can often cut through glass and is significantly tougher than its parent sandstone. The rounded shape is a result of hydraulic action and abrasion in moving water.

Field Identification & Locations

Identify by its hardness (it will scratch a steel knife) and its rounded, smooth cobble shape. Often found in riverbeds, glacial deposits, and sedimentary basins. Common in areas with ancient mountain-building history.

Identified on: 4/19/2026

Mode: Standard