Ferruginous Quartz (River Pebble)

Physical Properties

Hardness: 7 (Mohs scale); Color: Tan and olive-green with brown/orange iron staining; Luster: Vitreous to waxy (when wet); Crystal structure: Hexagonal (trigonal habit); Cleavage: None (conchoidal fracture).

Formation & Geological History

Formed from silica-rich hydrothermal fluids or within metamorphic rocks, then eroded and rounded by stream or river action. Iron impurities (hematite or goethite) seeped into micro-fractures over time.

Uses & Applications

Aesthetics, decorative landscaping, tumbled stones, and as a collector's specimen for hobbyists interested in stream-worn minerals.

Geological Facts

Quartz is the second most abundant mineral in Earth's continental crust. This specific piece is a 'river pebble,' meaning its smooth shape was sculpted by thousands of years of tumbling in water.

Field Identification & Locations

Identify by its hardness (cannot be scratched by a steel knife) and its smooth, water-worn texture. Commonly found in riverbeds, glacial tills, and beaches worldwide.

Identified on: 4/21/2026

Mode: Standard