Yellow Quartzite Pebble

Physical Properties

Hardness: 7 on Mohs scale; Color: Yellow to tan; 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 under intense heat and pressure, often during mountain-building events. This specimen has been rounded by fluvial or glacial transport.

Uses & Applications

Used primarily in landscaping, decorative gravel, and as a construction aggregate. High-purity quartzite is used to produce silica sand for glassmaking.

Geological Facts

Quartzite is so hard and durable that it often remains as resistant ridges or peaks even after surrounding softer rocks have eroded away over millions of years.

Field Identification & Locations

Identify by its ability to scratch glass and its grainy, sandpaper-like texture beneath a polished surface. Common in riverbeds, glacial deposits, and sedimentary basins.

Identified on: 5/4/2026

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