Rock Identifier
Tumbled yellow-orange chalcedony (likely carnelian or jasper) (Microcrystalline quartz, SiO₂; iron-oxide coloration) — mineral
mineral

Tumbled yellow-orange chalcedony (likely carnelian or jasper)

Microcrystalline quartz, SiO₂; iron-oxide coloration

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; orange-yellow to brown, translucent to opaque, waxy/glassy luster, cryptocrystalline quartz with no visible cleavage. The smooth rounded surface indicates tumbling or natural abrasion.

Identified More mineral
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Physical properties

Hardness about 6.5–7 Mohs; orange-yellow to brown, translucent to opaque, waxy/glassy luster, cryptocrystalline quartz with no visible cleavage. The smooth rounded surface indicates tumbling or natural abrasion.

Formation & geological history

Forms when silica-rich groundwater fills cavities or fractures, later colored by iron oxides; commonly Cenozoic to older volcanic and sedimentary settings. Exact identification and age require testing or microscopy.

Uses & applications

Used for beads, cabochons, carvings, ornaments, and lapidary practice; attractive translucent material has modest jewelry value.

Geological facts

Carnelian is the more translucent red-orange variety of chalcedony, while opaque iron-rich material is generally called orange or yellow jasper. The specimen may also be dyed or surface-coated.

Field identification & locations

Look for conchoidal fracture, quartz-like hardness, and resistance to scratching by a steel blade; it should scratch glass but not be scratched by steel. Common sources include India, Brazil, Uruguay, Madagascar, and the western United States.