mineral

Iron-stained quartz or chalcedony

Silicon dioxide, SiO₂; likely microcrystalline quartz with iron-oxide staining

AI-generated identification · may be incorrect

Hardness 6.5–7 Mohs; translucent cream, honey, and brown coloration; vitreous to waxy luster; conchoidal fracture; no visible cleavage; trigonal quartz or cryptocrystalline structure. The orange-brown tones are likely limonite/goethite coatings or inclusions.

Identified September 1, 2026More mineral →

Explore Iron-stained quartz or chalcedony 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

Forms when silica precipitates from groundwater in cavities, fractures, or volcanic rocks, with later oxidation of iron producing the warm coloration. Its exact geological age cannot be determined from the image; similar material occurs in hydrothermal veins and weathered host rocks worldwide.

Uses & applications

Used as a lapidary and ornamental material, especially when polished or tumbled; attractive pieces may be sold as jasper, chalcedony, or included quartz.

Geological facts

The specimen appears rough and naturally fractured rather than crystalline, so a precise identification requires a hardness, streak, translucency, and acid test. It may also be a small iron-stained agate or jasper fragment.

Field identification & locations

Common in silica-rich volcanic and sedimentary terrains, including Brazil, Uruguay, Madagascar, India, and the western United States. A glassy fracture and ability to scratch ordinary glass support quartz/chalcedony identification.