mineral

Orange chalcedony / iron-stained agate

Microcrystalline quartz (SiO₂), likely limonite/goethite-stained chalcedony

AI-generated identification · may be incorrect

Typically Mohs 6.5–7, orange to yellow-orange, waxy to dull luster, cryptocrystalline quartz with no visible cleavage; density about 2.6 g/cm³. The rough surface and porous-looking cavities may also indicate iron-rich jasper rather than pure chalcedony.

Identified August 13, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich groundwater fills cavities or fractures, later colored by oxidized iron minerals; commonly Cenozoic to older, depending on host rock. Exact age and locality cannot be determined from the image.

Uses & applications

Used as a lapidary stone for carvings, cabochons, beads, and decorative specimens; attractive pieces have modest collector value.

Geological facts

Its vivid orange color is usually produced by hematite, limonite, or goethite inclusions rather than the quartz itself. A sharp edge or freshly broken surface may reveal translucent chalcedony.

Field identification & locations

Common in volcanic terrains and sedimentary iron-rich environments worldwide, including Brazil, Mexico, India, Madagascar, and the western United States. Test with a steel file or streak plate cautiously: quartz resists steel and leaves a white streak, while soft iron coatings may rub off.