mineral

Dyed Agate

Chalcedony (Silicon Dioxide, SiO2)

Hardness: 6.5-7 Mohs; Color: Naturally translucent gray/brown but dyed purple, blue, and magenta here; Luster: Vitreous to waxy; Crystal structure: Hexagonal (cryptocrystalline); Specific gravity: 2.58-2.64

Hardness: 6
Luster: Vitreous to waxy

Identified June 8, 2026More mineral →

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Physical properties

Formation & geological history

Formed in cavities of volcanic or sedimentary rocks through the deposition of silica from groundwater. The vivid neon colors are the result of artificial dyeing, a process used on agates since Roman times.

Uses & applications

Commonly used in jewelry, decorative beads, bookends, and ornaments due to its hardness and ability to take a high polish.

Geological facts

While agate is naturally banded, the neon purple and blue hues seen here do not occur naturally; agates are very porous, allowing them to absorb chemical dyes easily.

Field identification & locations

Identify by the characteristic banding patterns and waxy luster. In the field, look for nodules with a rough exterior and a translucent, banded interior. Found globally in places like Brazil, Uruguay, and India.