Yellow Quartzite Pebble

Physical Properties

Hardness: 7 (Mohs scale), Color: Yellow-tan, Luster: Vitreous to dull (waxy), Crystal Structure: Trigonal/Hexagonal (microcrystalline), Cleavage: Indistinct/Conchoidal fracture, Specific Gravity: 2.6-2.65

Formation & Geological History

Formed through the metamorphism of quartz-rich sandstone. High heat and pressure Recrystallize quartz grains into a dense, interlocking mosaic of crystals. Often found as rounded river pebbles due to water erosion.

Uses & Applications

Used as decorative landscaping stones, ballast in construction, and when crushed, as a source for glass manufacturing. Smooth pebbles like this are popular in aquarium decor and rock tumbling.

Geological Facts

Quartzite is so tough that it often outlasts the surrounding rocks; it is more durable than many other common minerals and can actually scratch steel. Its yellow color often comes from iron oxide impurities trapped during metamorphism.

Field Identification & Locations

Identify by its extreme hardness (cannot be scratched by a knife) and its grainy, sugary texture under a hand lens. Commonly found in riverbeds, glacial deposits, and mountain ranges. It is an indicator of previous intense tectonic activity.

Identified on: 4/13/2026

Mode: Standard