mineral

Tumbled orange chalcedony or common opal

Microcrystalline quartz (SiO₂), possibly hydrated silica opal (SiO₂·nH₂O)

AI-generated identification · may be incorrect

Small rounded, translucent-to-opaque orange-beige specimen with a waxy luster and no visible crystal faces. Chalcedony is Mohs 6.5–7 with conchoidal fracture; opal is softer, Mohs 5.5–6.5, and has lower specific gravity (about 2.0–2.2).

Identified August 25, 2026More mineral →

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At a glance

Common name: Tumbled orange chalcedony or common opal
Scientific name: Microcrystalline quartz (SiO₂), possibly hydrated silica opal (SiO₂·nH₂O)
Category: mineral
Identified: August 25, 2026
Method: Standard

AI Estimated Value

About $1–$10 for a small common tumbled piece; approximately $10–$40 if unusually translucent, strongly colored, or confirmed as quality carnelian.

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

Likely silica deposited from groundwater in cavities, fractures, or volcanic rocks; orange color commonly comes from iron oxides. The photograph cannot establish a precise geological age or distinguish chalcedony from common opal confidently.

Uses & applications

Used as a lapidary and craft material, cabochon, bead, tumbled stone, or inexpensive decorative specimen; not typically valuable as gemstone-grade material.

Geological facts

The orange coloration is characteristic of iron-bearing silica, sometimes marketed as carnelian when the material is sufficiently translucent and saturated.

Field identification & locations

Field clues include waxy luster, translucency, curved fracture, and inability to scratch it with a steel knife if chalcedony. Common sources include India, Brazil, Uruguay, Madagascar, Mexico, and the western United States; a hardness or refractive-index test is needed for confirmation.