mineral

Tumbled yellow-brown quartz-rich pebble

Chalcedony or iron-stained quartz; exact identification requires testing

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs, opaque yellow-gold to brown, waxy to dull luster, very fine-grained cryptocrystalline silica; no visible cleavage and conchoidal fracture. The rounded shape indicates natural water wear or tumbling.

Identified September 22, 2026More mineral →

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Physical properties

Formation & geological history

Likely formed as silica-rich chalcedony or quartz in a cavity, vein, or weathered host rock, with iron oxides producing the yellow-brown color. Its geological age cannot be determined from the photograph.

Uses & applications

Common as a lapidary, carving, cabochon, and decorative stone; similar material is used for gravel and aggregate. It has modest collector value unless its locality or pattern is distinctive.

Geological facts

Possible names include yellow jasper, iron-stained chalcedony, or quartzite, but these cannot be separated confidently visually. A white streak and resistance to scratching by a steel knife support quartz-rich material.

Field identification & locations

Common in stream gravels and weathered silica-bearing rocks worldwide, especially volcanic and hydrothermal regions. Test hardness, streak, translucency at thin edges, and specific gravity; acid testing is generally uninformative.