mineral

Tumbled banded agate

Chalcedony, a microcrystalline variety of quartz (SiO₂)

AI-generated identification · may be incorrect

Polished pebble with purple-gray and cream-brown bands; waxy to vitreous luster, Mohs hardness 6.5–7, trigonal quartz structure, and no visible cleavage. The image does not allow confident identification of a specific agate variety.

Identified October 11, 2026More mineral →

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Physical properties

Formation & geological history

Agate forms as silica-rich fluids fill cavities and deposit successive chalcedony layers, commonly in volcanic rocks. Its age depends on the host rock and cannot be determined from appearance alone.

Uses & applications

Used for jewelry, beads, ornaments, and lapidary collections; its hardness and polish make it durable for decorative objects.

Geological facts

Agate banding records changes in silica deposition and impurities during growth; tumbling smooths the stone without changing its geological identity.

Field identification & locations

Look for translucent, curved or layered bands and a smooth, glassy-waxy surface; agates occur worldwide, especially in volcanic regions and stream gravels. This appears to be a shaped, polished specimen, but its exact locality is unknown.