Orange Quartzite (River Pebble)

Physical Properties

Hardness: 7 (Mohs scale); Color: Orange to honey-yellow due to iron oxide impurities; Luster: Vitreous to waxy (especially when water-worn); Crystal structure: Hexagonal (microcrystalline); Cleavage: None, exhibits conchoidal fracture; Specific gravity: 2.63 - 2.65

Formation & Geological History

Formed through the metamorphism of quartz-rich sandstone. Under intense heat and pressure, quartz grains recrystallize and fuse together. This specific specimen has been further shaped by fluvial erosion (river action), resulting in a smooth, rounded pebble shape.

Uses & Applications

Used primarily for decorative landscaping, aquarium gravel, and occasionally as minor lapidary material for tumbling. Industrial quartzite is used in glassmaking and as crushed stone for construction.

Geological Facts

Quartzite is harder and more durable than the sandstone it originates from. It is so tough that it often breaks through the quartz grains rather than around them. The orange tint is often caused by trace amounts of hematite or limonite staining.

Field Identification & Locations

Identify in the field by its hardness (it will easily scratch glass) and its sugary, crystalline texture under a magnifying lens. Commonly found in riverbeds, glacial tills, and mountainous regions where ancient sedimentary basins were uplifted.

Identified on: 4/13/2026

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