Quartzite with Garnet

Physical Properties

Hardness: 7 (Mohs), Color: Light grey to tan matrix with reddish-pink inclusions, Luster: Vitreous to dull, Crystal structure: Granoblastic (massive), Specific gravity: 2.6-2.8

Formation & Geological History

Formed through the regional metamorphism of quartz-rich sandstone. High pressure and temperature recrystallize quartz grains and facilitate the growth of almandine garnet crystals from impurities during the Proterozoic or Paleozoic eras.

Uses & Applications

Used as crushed stone for construction, road ballast, and decorative landscaping. High-quality specimens with intact garnets are popular for geological study and mineral collecting.

Geological Facts

Quartzite is so tough that it often survives intense weathering that wears away surrounding rock; it typically forms the crest of rugged mountain ranges and ridges.

Field Identification & Locations

Identify by its ability to scratch glass and its granular, sugary texture on fresh breaks. It is commonly found in the Appalachian Mountains and the Canadian Shield. Look for characteristic red garnet 'spots' in a hard, non-fizzing matrix.

Identified on: 5/19/2026

Mode: Standard