mineral
Tumbled orange chalcedony or common opal
Microcrystalline quartz (SiO₂), possibly hydrated silica opal (SiO₂·nH₂O)
AI-generated identification · may be incorrectSmall 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).
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Physical properties
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).
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.
