Ferruginous Quartz (Iron-stained Quartz)

Physical Properties

Hardness: 7 on Mohs scale; Color: Rusty red, orange, or brown with white/clear areas; Luster: Vitreous (glassy) to greasy; Crystal Structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65.

Formation & Geological History

Formed from silica-rich hydrothermal fluids where iron oxides like hematite or goethite are present, staining the quartz during or after crystallization. Often found in vein deposits or weathered riverbeds.

Uses & Applications

Mainly used as a collector specimen, in lapidary work (cabochons), or as decorative 'healing crystals' in metaphysical markets.

Geological Facts

The reddish-brown color is caused by microscopic particles of iron oxide trapped within the crystal lattice or along fractures. It is commonly referred to in the trade as 'Hematoid Quartz' or 'Fire Quartz'.

Field Identification & Locations

Identify in the field by its high hardness (cannot be scratched by a steel knife) and its distinct waxy-to-glassy luster despite the iron staining. Commonly found in river gravels or areas with volcanic activity.

Identified on: 4/28/2026

Mode: Standard