mineral

Tumbled chalcedony (likely pale agate or quartz pebble)

Microcrystalline silica, SiO₂ (chalcedony; possibly quartz-rich agate)

AI-generated identification · may be incorrect

Cream to honey-yellow, translucent, waxy-to-vitreous luster, with indistinct microcrystalline structure and no obvious cleavage. Mohs hardness is about 6.5–7; specific gravity approximately 2.6. The rounded form appears naturally water-worn or tumbled, with surface fractures or internal veining.

Identified August 8, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich groundwater fills cavities and fractures, precipitating cryptocrystalline quartz; agate varieties may develop subtle bands. The specimen may be a river pebble or human-tumbled piece. Its exact geological age cannot be determined visually.

Uses & applications

Used as a lapidary material for cabochons, beads, carvings, and polished stones; durable aggregate or construction use is possible but uncommon for pieces this size.

Geological facts

Chalcedony can be translucent even when pale and opaque-looking. Yellow coloration may result from iron staining or included iron minerals; dyeing is also possible in commercial tumbled stones.

Field identification & locations

A glassy/waxy surface, lack of cleavage, rounded pebble form, and resistance to scratching distinguish it from calcite. It is regionally plausible near 48.7°N, 11.7°E, where Alpine-derived river gravels can contain quartz and chalcedony; confirm with a steel scratch test and inspection for agate banding.