Rock Identifier
Tumbled brown stone, possibly jasper or iron-rich chert (Indeterminate; likely microcrystalline quartz (SiO₂) with iron-oxide coloration) — mineral
mineral

Tumbled brown stone, possibly jasper or iron-rich chert

Indeterminate; likely microcrystalline quartz (SiO₂) with iron-oxide coloration

AI-generated identification · may be incorrect

Smooth, rounded, polished surface; opaque orange-brown color with subdued waxy to dull luster. If jasper/chert, hardness is about Mohs 6.5–7, with no visible cleavage and a fine cryptocrystalline structure; the image alone cannot confirm composition.

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Physical properties

Smooth, rounded, polished surface; opaque orange-brown color with subdued waxy to dull luster. If jasper/chert, hardness is about Mohs 6.5–7, with no visible cleavage and a fine cryptocrystalline structure; the image alone cannot confirm composition.

Formation & geological history

Jasper or chert forms when silica-rich fluids replace or cement sediment, with iron oxides producing the brown-orange color; formation ages vary widely from Precambrian to younger deposits. Its shape appears human-tumbled or naturally water-worn.

Uses & applications

Commonly used for cabochons, beads, decorative stones, and lapidary objects; lower-grade pieces are inexpensive ornamental material.

Geological facts

A definitive identification requires a fresh surface, translucency check, streak, hardness test, and ideally specific gravity or microscopy. Similar-looking materials include brown chalcedony, ironstone, petrified wood, and ordinary river rock.

Field identification & locations

Common in gravel beds and silica-rich volcanic or sedimentary terrains worldwide; quartz-rich material should scratch glass, while a steel blade generally will not scratch it. Estimated value: $2–$20 for a common tumbled stone, or $20–$100 if unusually attractive or gem-quality.