mineral

Eye Agate

Silicon Dioxide (SiO2) - Banded Chalcedony

AI-generated identification · may be incorrect

Hardness: 6.5-7 (Mohs scale), Color: Concentric bands of white, tan, and brown, Luster: Waxy to vitreous, Crystal Structure: Trigonal (microcrystalline), Cleavage: None (conchoidal fracture), Specific Gravity: 2.58-2.64

Hardness: 6

Identified February 20, 2026More mineral →

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Physical properties

Formation & geological history

Formed as a secondary mineral in volcanic rock cavities (vesicles) through the deposition of silica from groundwater. The 'eye' effect is produced by concentric layering around a central seed or gas bubble over thousands of years.

Uses & applications

Primarily used in jewelry (rings, pendants), as talismans in cultural practices, and as collector specimens for lapidary artists.

Geological facts

Also known as 'Third Eye Agate' or 'Shiva Eye' in some spiritual traditions, it has been used for millennia as an amulet against the 'evil eye'. The concentric rings are natural, though sometimes enhanced by heat treatment.

Field identification & locations

Identify by looking for perfect concentric circles that do not break through the surface like paint. Found commonly in Brazil, India, and the Lake Superior region (USA). Collectors look for high symmetry and sharp contrast in the rings.