mineral

Tumbled jasper or iron-rich chalcedony

Microcrystalline quartz (SiO₂), likely colored by iron oxides

AI-generated identification · may be incorrect

Small rounded, polished brown-red pebble with orange translucency and a glossy vitreous-to-waxy luster. Quartz hardness is about 7 Mohs; no obvious cleavage, conchoidal fracture, and specific gravity near 2.6. The image does not resolve whether it is jasper, carnelian, or iron-stained agate.

Identified August 8, 2026More mineral →

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Physical properties

Formation & geological history

Formed when silica-rich groundwater filled cavities or fractures, with iron minerals producing the reddish-brown color; later naturally or mechanically rounded. Such material commonly formed in sedimentary or volcanic settings during the Cenozoic or older periods.

Uses & applications

Used as an inexpensive lapidary stone for cabochons, beads, carvings, and tumbled specimens. Typical value is modest unless it has exceptional patterning or provenance.

Geological facts

The translucent orange-brown areas favor carnelian or iron-stained chalcedony, while opaque zones favor jasper. A scratch test with steel or a glass tile can help distinguish quartz from softer look-alikes.

Field identification & locations

Plausible around 48.7°N, 11.7°E, where transported Alpine gravels and river deposits can contain quartz, chalcedony, and jasper. Confirm with a fresh surface, strong backlight, and hardness testing; avoid damaging a potentially attractive specimen.