Yellow Quartzite (River Pebble)

Physical Properties

Hardness: 7 on Mohs scale; Color: Yellow-tan to cream; Luster: Vitreous to waxy; Crystal Structure: Trigonal (microcrystalline masses); Cleavage: None; Specific Gravity: 2.6 - 2.65

Formation & Geological History

Formed from the metamorphism of quartz-rich sandstone under extreme heat and pressure, usually associated with regional tectonic activity. This specific specimen appears water-worn, indicating erosion and transport via river systems.

Uses & Applications

Used as decorative gravel in landscaping, as an abrasive, and historically as a material for masonry. Highly durable in construction.

Geological Facts

Quartzite is so strong that it will break through the quartz grains rather than along the boundaries between them, unlike its parent stone, sandstone. It is often mistake for marble, but is much harder and won't react with acid.

Field Identification & Locations

Identify in the field by its hardness (it can scratch glass) and its granular, sugary texture on fresh breaks. Very common in riverbeds and mountainous regions globally.

Identified on: 4/18/2026

Mode: Standard