Yellow Quartzite (River Pebble)

Physical Properties

Hardness: 7 on Mohs scale; Color: Yellowish-tan to golden brown due to iron inclusions; Luster: Vitreous to dull; Crystal structure: Hexagonal/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, recrystallizing individual grains into a fused mass. This specific specimen has been further shaped and polished by fluvial (river) erosion.

Uses & Applications

Commonly used as decorative landscaping stone, in construction aggregates, or as tumbled 'worry stones' and pocket charms.

Geological Facts

Quartzite is so hard that it can scratch glass and even steel. It is more resistant to weathering than the original sandstone it formed from, which is why it often survives as smooth river pebbles.

Field Identification & Locations

Identify in the field by its hardness (will scratch a glass bottle) and its 'sugary' texture on a fresh break. Commonly found in riverbeds, glacial deposits, and mountain ranges.

Identified on: 4/13/2026

Mode: Standard