mineral

Ferruginous Quartz (Carnelian-tinted Quartz)

Silicon Dioxide (SiO2) with Iron Oxide inclusions

AI-generated identification · may be incorrect

Hardness: 7 (Mohs scale); Color: Orange-red to tan due to hematite/limonite staining; Luster: Vitreous to waxy; Crystal structure: Trigonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Hardness: 7 (Mohs scale)
Color: Orange-red to tan due to hematite/limonite staining
Luster: Vitreous to waxy

Identified March 29, 2026More mineral →

Explore Ferruginous Quartz (Carnelian-tinted Quartz) in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Formed in hydrothermal veins or as a secondary mineral in sedimentary environments. Common in beach gravels and riverbeds where it has been smoothed by water erosion. Geological age can range from millions to billions of years depending on source rock.

Uses & applications

Used primarily for lapidary work (tumbling, cabochons), metaphysical collecting, and historically for signet rings and beads due to its hardness and warm color.

Geological facts

This specimen appears to be a 'river rock' or 'beach pebble' variant of quartz containing iron oxide. The orange hue is caused by the same chemical process that creates rust, where iron minerals seep into the microscopic cracks of the quartz crystal lattice.

Field identification & locations

Identify in the field by its translucency when held to light and its inability to be scratched by a steel knife. Commonly found in Great Lakes regions, coastal beaches, and desert washes. Collectors look for high translucency and deep 'burnt orange' saturation.