mineral

Blue-dyed banded agate

Microcrystalline quartz (SiO₂), chalcedony variety

AI-generated identification · may be incorrect

Hardness 6.5–7 Mohs; vivid blue color likely dye-enhanced, with white-to-blue concentric banding; vitreous to waxy luster, cryptocrystalline structure, no visible cleavage, specific gravity about 2.6.

Identified August 11, 2026More mineral →

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Physical properties

Formation & geological history

Agate forms when silica-rich groundwater fills cavities in volcanic rock, depositing successive chalcedony layers over long periods, commonly during the Cenozoic or older volcanic episodes. The specimen has been cut, polished, and probably dyed to intensify its blue color.

Uses & applications

Used for cabochons, beads, carvings, ornaments, and lapidary collections; agate is durable but not generally a high-value gemstone.

Geological facts

The banding records repeated changes in silica chemistry and fluid conditions during cavity filling. Dye commonly concentrates along porous bands and may fade or bleed with harsh chemicals or prolonged sunlight.

Field identification & locations

Common localities include Brazil, Uruguay, Mexico, India, Madagascar, and the United States. Identify it by curved concentric chalcedony bands, lack of cleavage, glassy polish, and a hardness sufficient to scratch ordinary glass.