mineral

Tumbled carnelian (red chalcedony)

Carnelian, a microcrystalline variety of quartz; SiO₂, commonly colored by iron oxides

AI-generated identification · may be incorrect

Mohs hardness 6.5–7; orange-red to brown-red, translucent edges, waxy to vitreous luster, cryptocrystalline quartz with no visible cleavage. Specific gravity is approximately 2.6.

Identified August 20, 2026More mineral →

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At a glance

Common name: Tumbled carnelian (red chalcedony)
Scientific name: Carnelian, a microcrystalline variety of quartz; SiO₂, commonly colored by iron oxides
Category: mineral
Identified: August 20, 2026
Method: Standard

AI Estimated Value

Approximately $3–$15 for this small tumbled group; fine natural, strongly translucent specimens or larger polished pieces may sell for $20–$100+.

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

Mohs hardness 6.5–7; orange-red to brown-red, translucent edges, waxy to vitreous luster, cryptocrystalline quartz with no visible cleavage. Specific gravity is approximately 2.6.

Formation & geological history

Forms when silica-rich groundwater fills cavities and fractures, with iron impurities producing the red-orange color; commonly Cenozoic to older volcanic or sedimentary host rocks. These pieces are polished/tumbled geological specimens.

Uses & applications

Used for beads, cabochons, carvings, decorative objects, and low-cost jewelry; historically used for seals and amulets. Common tumbled pieces have modest collector value.

Geological facts

Carnelian is closely related to sard and agate, differing mainly in color and translucency. Heating can intensify its red coloration, and some commercial material is dyed.

Field identification & locations

Identify by its warm red-orange color, waxy luster, translucency, and hardness; it should scratch glass but not quartz. Common sources include India, Brazil, Uruguay, Madagascar, and Germany.