Quartzite Pebble

Physical Properties

Hardness: 7 (Mohs scale), Color: Creamy white with tan/brown iron staining, Luster: Vitreous to waxy (especially when river-worn), Crystal structure: Hexagonal (microcrystalline), Cleavage: None (conchoidal fracture), Specific gravity: 2.6-2.7

Formation & Geological History

Formed through the metamorphism of quartz-rich sandstone subjected to high heat and pressure. This specific specimen has been further shaped by fluvial (river) or glacial erosion, resulting in its smooth, rounded 'pebble' texture. Generally ranges from Proterozoic to more recent geological eras.

Uses & Applications

Used in construction as crushed stone, in glass manufacturing, as a decorative stone in landscaping, and sometimes as a grinding medium in industrial mills. Small smooth pebbles like this are often kept as pocket stones or used in rock tumblers.

Geological Facts

Quartzite is so hard that it will scratch glass and steel. This specimen shows 'concoidal' fractures or impact scars common in river-transported rocks. It is one of the most durable rocks on Earth's surface.

Field Identification & Locations

Identify in the field by its extreme hardness and inability to be scratched by a steel knife. It often feels denser and smoother than limestone. Commonly found in riverbeds, beaches, and glacial till worldwide.

Identified on: 4/19/2026

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