mineral

Banded agate (likely polished/tumbled)

Agate, a banded variety of chalcedony (microcrystalline quartz, SiO₂)

AI-generated identification · may be incorrect

Translucent blue-gray and white curved bands with a vitreous to waxy luster; Mohs hardness 6.5–7, trigonal quartz structure, no cleavage, specific gravity about 2.6.

Identified October 11, 2026More mineral →

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Physical properties

Translucent blue-gray and white curved bands with a vitreous to waxy luster; Mohs hardness 6.5–7, trigonal quartz structure, no cleavage, specific gravity about 2.6.

Formation & geological history

Silica-rich fluids deposited successive chalcedony layers in a cavity, commonly in volcanic rock. Such deposits form across geologic time; the specimen’s source and age cannot be determined from the image.

Uses & applications

Used for jewelry, carvings, ornaments, and collecting; agate is also used for small technical components and abrasives.

Geological facts

Agate’s distinctive bands record changing conditions as silica precipitated, and many agates are polished to reveal their patterns.

Field identification & locations

Look for fine, curved or concentric bands and a hard, glassy-to-waxy surface; common sources include Brazil, Uruguay, India, and the United States. The pictured piece appears polished, so its exact identification is uncertain.