mineral

Tumbled brown jasper (probable)

Microcrystalline quartz/chalcedony, SiO₂, with iron-oxide impurities

AI-generated identification · may be incorrect

Opaque mustard-brown, smoothly rounded and polished, with a dull-to-waxy luster; quartz hardness is about 6.5–7 Mohs, no visible cleavage, and specific gravity near 2.6. The image alone cannot confirm the exact variety; it could also be iron-stained chert or another common silicate pebble.

Identified September 3, 2026More mineral →

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Physical properties

Formation & geological history

Jasper forms when silica-rich fluids replace or cement sediments, commonly with iron oxides producing brown, red, or yellow colors. Formation ages vary widely, from Precambrian to recent, depending on the deposit.

Uses & applications

Used for cabochons, beads, carvings, bookends, and inexpensive decorative objects; suitable for tumbling and minor lapidary work.

Geological facts

Its color commonly comes from hematite or limonite inclusions rather than the quartz itself. A glassy scratch test and lack of reaction with dilute acid support a quartz-rich identification.

Field identification & locations

Common in river gravels and silica-rich volcanic or sedimentary terrains worldwide; inspect for uniform opacity, waxy luster, and hardness sufficient to scratch glass. Typical value is $2–$15 for a small tumbled piece, or $10–$50 if unusually attractive or from a recognized locality.