Quartzite Pebble (with Iron Inclusions)

Physical Properties

Hardness: 7 (Mohs scale), Color: tan to orange-red due to hematite staining, Luster: vitreous to dull, Crystal structure: granular/microcrystalline, Specific gravity: 2.6-2.7

Formation & Geological History

Formed through the metamorphism of quartz-rich sandstone under intense heat and pressure. This specimen shows significant rounding from alluvial or glacial transport, making it a river pebble.

Uses & Applications

Common quartzite is used for construction aggregate, railway ballast, and road surfacing. Smooth pebbles like this are often used in landscaping or as aquarium decor.

Geological Facts

Quartzite is so tough that it often survives millions of years of river transport and erosion that would pulverize other rock types. The reddish spots are likely microscopic iron oxide (rust) inclusions.

Field Identification & Locations

Identify by its ability to scratch glass and its grainy, sandpaper-like texture inside despite the external smoothness. Commonly found in riverbeds, glacial tills, and beaches.

Identified on: 4/29/2026

Mode: Standard