gemstone

Tumbled carnelian (orange chalcedony)

Carnelian, a variety of microcrystalline quartz (SiO₂), often colored by iron oxides

AI-generated identification · may be incorrect

Mohs hardness 6.5–7; translucent orange to reddish-orange, vitreous to waxy luster, cryptocrystalline structure, with no visible cleavage and conchoidal fracture. The rounded, polished shape indicates human processing.

Identified September 7, 2026More gemstone →

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At a glance

Common name: Tumbled carnelian (orange chalcedony)
Scientific name: Carnelian, a variety of microcrystalline quartz (SiO₂), often colored by iron oxides
Category: gemstone
Identified: September 7, 2026
Method: Standard

AI Estimated Value

Approximately $2–$15 for a common tumbled stone; $20–$100+ for large, vividly colored, naturally patterned, or finely finished pieces.

Not an official valuation

AI estimate for general interest only — not an appraisal. Actual value depends on condition, provenance, and market demand. Verify with a professional before buying, selling, or insuring.

This identification was generated by AI and may contain errors. Verify important details before relying on them — and never use an AI result to judge whether a specimen is safe to handle. Read the full disclaimer

Physical properties

Formation & geological history

Forms when silica-rich groundwater fills cavities and fractures in volcanic rocks, with iron producing the orange-red color; deposits range from Paleozoic to Cenozoic in age. Common sources include India, Brazil, Uruguay, Madagascar, and the United States.

Uses & applications

Used for beads, cabochons, carvings, seals, and inexpensive jewelry; tumbled pieces are popular decorative and lapidary specimens.

Geological facts

Carnelian is chalcedony rather than a separate mineral species; heating can intensify its red-orange color. It was widely used for ancient seals and engraved gems.

Field identification & locations

Identify it by its even orange color, translucency, quartz-like hardness, and lack of cleavage; it should scratch glass but not be scratched by a steel blade. Natural banding or agate-like zoning may occur.