mineral

Tumbled banded agate

Chalcedony (microcrystalline quartz), SiO₂

AI-generated identification · may be incorrect

Hardness 6.5–7 Mohs; translucent white, cream, and peach-pink bands with waxy to vitreous luster. It has cryptocrystalline quartz structure, no visible cleavage, and conchoidal fracture; the smooth surface indicates tumbling and polishing.

Identified August 19, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich groundwater fills cavities in volcanic rock, depositing successive layers of chalcedony over long periods, commonly during the Cenozoic or older volcanic episodes. The specimen’s exact locality cannot be determined from the image.

Uses & applications

Used for cabochons, beads, carvings, ornaments, and lapidary collectibles; agate is also used for durable decorative and occasionally precision-industrial objects.

Geological facts

The parallel pale bands are characteristic of agate, while the pink coloration may result from iron oxides or other trace impurities. Agate is a variety of quartz rather than a separate mineral species.

Field identification & locations

Identify it by translucency, curved or parallel banding, waxy luster, and quartz-like hardness; it should resist scratching by a steel knife. Common sources include Brazil, Uruguay, India, Mexico, Madagascar, and the United States.