Quartzite Pebble (with Quartz veins)

Physical Properties

Hardness: 7 (Mohs scale); Color: Brownish-tan with translucent white veins; Luster: Vitreous to waxy (when wet or polished); Crystal structure: Trigonal (microcrystalline); Cleavage: None/Conchoidal fracture; Specific Gravity: 2.65

Formation & Geological History

Formed through the metamorphism of quartz-rich sandstone under intense heat and tectonic pressure. The original sand grains recrystallize into an interlocking mosaic of quartz crystals. This specific specimen shows signs of water-smoothing (rounded shape) from river or coastal transport.

Uses & Applications

Used primarily in construction as crushed stone or ballast. Often used as decorative landscaping rocks or garden stones. High-purity quartzite is used in the glass and chemical industries.

Geological Facts

Quartzite is so hard and chemically resistant that it often forms the crests of ridges and resistant hills. It is harder than steel and will easily scratch glass. Many quartzite formations are billions of years old, dating back to the Precambrian era.

Field Identification & Locations

Identify in the field by its extreme hardness and grainy texture that resembles sandpaper but feels smooth due to recrystallization. Unlike sandstone, quartzite breaks across its grain rather than around them. Commonly found in riverbeds and mountainous glacial till.

Identified on: 4/22/2026

Mode: Standard