Yellow Quartzite (River Pebble)

Physical Properties

Hardness: 7 on Mohs scale; Color: Yellow, honey-tan, or brownish-orange due to iron staining; Luster: Vitreous to waxy; Structure: Granular/Crystalline; Cleavage: None (conchoidal fracture); Specific Gravity: 2.6 - 2.8.

Formation & Geological History

Formed through the metamorphism of quartz sandstone under intense heat and pressure. This specific specimen is a water-worn river pebble, likely shaped over thousands of years by fluvial erosion.

Uses & Applications

Used in landscaping (river rock), crushed stone for construction, and occasionally for lapidary work (tumbling) or as decorative gravel.

Geological Facts

Quartzite is so tough that it often survives long after the surrounding rocks have eroded away. The yellow color is usually caused by 'limonite' or iron oxide staining permeating the quartz grains.

Field Identification & Locations

Identify by its ability to scratch glass and its sugary, granular texture hidden beneath the smooth, water-worn surface. It is commonly found in riverbeds, glacial tills, and ancient beach deposits worldwide.

Identified on: 4/25/2026

Mode: Standard