Yellow Quartzite (River Pebble)

Physical Properties

Hardness: 7 (Mohs scale), Color: Ocher to yellowish-brown, Luster: Vitreous to waxy, Crystal structure: Trigonal (microcrystalline), Cleavage: None/Conchoidal fracture, Specific gravity: 2.6 – 2.7

Formation & Geological History

Formed from the metamorphism of quartz-rich sandstone. High heat and pressure Recrystallized grains into a dense rock. The rounded shape indicates extensive water erosion in a river or beach environment.

Uses & Applications

Commonly used as construction aggregate, ballast, and increasingly in decorative landscaping or as tumbled stones for terrariums.

Geological Facts

Quartzite is so hard and chemically resistant that it often remains as high points on mountains after surrounding rocks have eroded away. Iron oxide impurities are what give this specimen its yellow-orange hue.

Field Identification & Locations

Identify by its ability to scratch glass and its grainy, sugary texture when broken. It is extremely common in glacial till and riverbeds throughout North America and Europe.

Identified on: 4/13/2026

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