mineral

Polished banded agate

Agate, a banded variety of microcrystalline quartz (SiO₂)

AI-generated identification · may be incorrect

Hardness 6.5–7 Mohs; translucent gray, cream, and brown bands with a vitreous polish. It has a trigonal quartz structure, no cleavage, and specific gravity around 2.6.

Identified September 28, 2026More mineral →

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Physical properties

Hardness 6.5–7 Mohs; translucent gray, cream, and brown bands with a vitreous polish. It has a trigonal quartz structure, no cleavage, and specific gravity around 2.6.

Formation & geological history

Forms as silica-rich groundwater deposits chalcedony in cavities, commonly in volcanic rocks; individual agate bands may form over long periods during the Cenozoic or earlier.

Uses & applications

Used for jewelry, ornaments, carvings, and collector specimens; agate is also used for small tools and precision components.

Geological facts

The specimen appears to be a small polished agate slice or nodule, with curved bands and a speckled chalcedony zone.

Field identification & locations

Identify by its fine-grained quartz, curved color bands, and hardness sufficient to scratch glass; agates occur worldwide, especially in volcanic regions and stream gravels.