mineral

Chalcedony (likely agate or chert)

Microcrystalline quartz, SiO₂

AI-generated identification · may be incorrect

Hardness 6.5–7 Mohs; pale cream, gray, and yellow translucent zones with waxy to dull luster. It has cryptocrystalline quartz structure, no obvious cleavage, and a typical specific gravity near 2.6; the surface appears naturally weathered or roughly polished.

Identified August 15, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich groundwater fills cavities, veins, or fractures in volcanic and sedimentary rocks, commonly developing bands or cloudy fibrous textures. The specimen’s exact geological age and locality cannot be determined from the photograph.

Uses & applications

Used as decorative stone, cabochons, beads, carvings, and lapidary material; tougher varieties are also used for small tools and abrasives. Common material generally has modest collector value.

Geological facts

The visible pale swirling texture is consistent with chalcedony, possibly a weathered agate or chert, but lighting and the lack of a fresh edge prevent a precise identification.

Field identification & locations

Commonly found as rounded nodules in volcanic terrains, limestone cavities, river gravels, and sedimentary formations worldwide. Field tests include its waxy appearance, lack of cleavage, resistance to scratching by a steel blade, and inability to scratch glass unless the surface is fresh.