Quartzite Pebble

Hardness: 7 (Mohs scale), Color: light grey to white with slight translucency, Luster: Vitreous to waxy, Crystal structure: Hexagonal (microcrystalline), Cleavage: Indistinct, SG: 2.65.

Formed from the metamorphism of quartz-rich sandstone under intense heat and pressure. The individual quartz grains recrystallize into a dense, interlocking mosaic of crystals. This specimen is water-worn into a smooth pebble shape.

Commonly used as construction aggregate, railway ballast, and in the production of glass and silicon. Polished pebbles are used in landscaping and low-cost decorative crafts.

Quartzite is so tough that it often outlasts the surrounding rocks during erosion, frequently being found as pebbles in river beds or on beaches far from its original source.

Identify in the field by its extreme hardness; it will easily scratch glass and cannot be scratched by a steel nail. Look for a sugary texture on broken surfaces. Found globally in ancient mountain belts.