Quartzite with Hematite staining

Physical Properties

Hardness: 7 on Mohs scale; Color: Reddish-brown, grey, and translucent white; Luster: Vitreous to dull; Crystal structure: Hexagonal (microcrystalline); Cleavage: None; Specific gravity: 2.6-2.7

Formation & Geological History

Formed through the metamorphism of quartz sandstone under intense heat and pressure. The reddish-brown coloration is due to the presence of secondary iron minerals like hematite that seeped into the rock during or after formation.

Uses & Applications

Used as a decorative stone, in construction as crushed stone or road ballast, and sometimes as a component in glassmaking if high purity.

Geological Facts

Quartzite is so hard and chemically resistant that it often forms the caprock or spine of mountain ranges. It is much harder than the sandstone it originated from.

Field Identification & Locations

Identify in the field by its hardness (it will scratch glass) and its grainy, sugary texture that resembles sandpaper but feels smooth to the touch. Commonly found in folded mountain belts and glacial deposits.

Identified on: 4/18/2026

Mode: Standard