Ferruginous Quartz

Physical Properties

Hardness: 7 (Mohs scale); Color: Rusty orange to reddish-brown; Luster: Vitreous to waxy; Crystal Structure: Trigonal/Hexagonal; Cleavage: None/Conchoidal fracture; Specific Gravity: 2.65.

Formation & Geological History

Formed in igneous or metamorphic environments where iron-rich fluids precipitate into or coat quartz crystals. The orange color is due to the presence of iron oxide (hematite or limonite).

Uses & Applications

Commonly used as a lapidary material for tumbling, making beads, or as decorative garden stones. Also sought after by metaphysical collectors.

Geological Facts

Also known as Eisenkiesel, this variety of quartz gets its name from the Latin 'ferrum' meaning iron. It is one of the most common colored varieties of quartz found in riverbeds.

Field Identification & Locations

Identify in the field by its hardness (will scratch glass) and its characteristic 'rusty' orange-brown staining. Frequently found in gravel pits or along riverbanks in areas with iron deposits.

Identified on: 4/17/2026

Mode: Standard