Red Quartzite / Ferruginous Sandstone

Physical Properties

Hardness: 7 (Mohs scale), Color: reddish-brown to purple due to hematite, Luster: dull to vitreous, Crystal structure: microcrystalline/granular, Specific Gravity: 2.6-2.7

Formation & Geological History

Formed through the metamorphism of quartz-rich sandstone. High heat and pressure Recrystallize quartz grains into a dense, interlocking matrix. Often found in riverbeds after eroding from mountain ranges.

Uses & Applications

Used as crushed stone for road construction, railway ballast, and occasionally as decorative stone or landscaping rock due to its durability and color.

Geological Facts

Quartzite is so tough that it often breaks through the constituent sand grains rather than around them. It is one of the most weather-resistant rocks on the Earth's surface.

Field Identification & Locations

Identify in the field by its hardness (it will scratch glass) and its granular, sugary texture on fresh breaks. This rounded specimen indicates significant transport by water in a high-energy environment like a river.

Identified on: 4/26/2026

Mode: Standard