Dyed Agate

Hardness: 6.5-7 on the Mohs scale. Color: The top half is dyed an intense teal/blue, with distinct banding characteristic of agate. The bottom half is clear/white with internal fractures (often referred to as 'crackled' or 'frosted' when treated like this, though it appears to be naturally crystalline quartz or chalcedony transitioning into the banded portion). Luster: Vitreous (glassy). Crystal structure: Trigonal (microcrystalline/cryptocrystalline).

Agate naturally forms as nodules in volcanic rock or ancient lavas, in cavities produced by gas bubbles. It forms through the slow deposition of silica from groundwater. However, the vivid blue color in this piece is artificial, created by soaking the porous chalcedony/agate in chemical dyes (often a cobalt or iron solution, or synthetic dyes) followed by a setting process.

Used primarily in inexpensive jewelry, ornamental carvings, and lapidary crafts. The hole drilled at the top indicates it is intended to be worn as a pendant.

Dyeing agate is a very old practice, dating back to the ancient Romans. Because agate is relatively porous, it accepts dyes very well, allowing for bright, unnatural colors that appeal to consumers.

Identify dyed agate by its overly bright, uniform, or unnatural colors. Natural blue agates (like Blue Lace or Ellensburg Blue) have much paler, more subtle hues. Look for color concentrated in structural cracks or specific bands, which is a telltale sign of dye.