Riverstone Quartzite / Chalcedony Nugget

Physical Properties

Hardness: 7 (Mohs scale), Color: Yellowish-tan with grey inclusions, Luster: Waxy to vitreous, Crystal Structure: Hexagonal (microcrystalline), Cleavage: None/Conchoidal fracture, Specific Gravity: 2.65

Formation & Geological History

Formed from the recrystallization of quartz-rich sandstone under intense heat and pressure (metamorphism), then weathered and smoothed by water transport in a river environment.

Uses & Applications

Commonly used as decorative landscaping stone, in construction aggregates, or as tumbled 'pocket stones' for collectors and spiritual use.

Geological Facts

Quartzite is so durable that it can outlast the mountains it formed in. This particular specimen shows 'cortex' weathering, common in river-worn silica-based rocks.

Field Identification & Locations

Identify in the field by its inability to be scratched by a steel knife and its smooth, rounded 'potato' shape characteristic of fluvial erosion. Found globally in riverbeds and glacial deposits.

Identified on: 4/27/2026

Mode: Standard