mineral

Rounded banded agate pebble

Agate, microcrystalline quartz (SiO₂), commonly chalcedony with quartz bands

AI-generated identification · may be incorrect

Hardness 6.5–7; translucent gray, brown, and reddish bands; waxy to vitreous luster; cryptocrystalline structure with no visible cleavage and conchoidal fracture. The smooth shape is water-rounded.

Identified September 11, 2026More mineral →

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Physical properties

Hardness 6.5–7; translucent gray, brown, and reddish bands; waxy to vitreous luster; cryptocrystalline structure with no visible cleavage and conchoidal fracture. The smooth shape is water-rounded.

Formation & geological history

Silica-rich groundwater deposited successive microscopic layers in cavities of volcanic rock, likely during the Cenozoic or older; erosion later released and rounded it in a gravel beach or stream. Exact age and locality require testing.

Uses & applications

Primarily a collectible or lapidary stone; used for cabochons, beads, carvings, bookends, and polished ornaments. This small pebble has modest commercial value.

Geological facts

The specimen’s banding and translucency support agate, though the image alone cannot distinguish it confidently from jasper or banded chalcedony.

Field identification & locations

Look for curved parallel bands, translucency at thin edges, waxy luster, and hardness sufficient to scratch ordinary glass. Common sources include volcanic terrains in Brazil, Uruguay, Mexico, the western United States, and many gravel beaches.