Rock Identifier
Dyed and polished agate cabochon (Microcrystalline quartz (chalcedony), SiO₂; likely colored or composite agate) — gemstone
gemstone

Dyed and polished agate cabochon

Microcrystalline quartz (chalcedony), SiO₂; likely colored or composite agate

AI-generated identification · may be incorrect

Hardness 6.5–7 Mohs; waxy to vitreous luster; curved or banded chalcedony texture, with reddish-brown, blue, and green coloration. The vivid blue and sharply contrasting swirls strongly suggest dyeing, possibly in a polished bead or cabochon.

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Physical properties

Hardness 6.5–7 Mohs; waxy to vitreous luster; curved or banded chalcedony texture, with reddish-brown, blue, and green coloration. The vivid blue and sharply contrasting swirls strongly suggest dyeing, possibly in a polished bead or cabochon.

Formation & geological history

Agate forms when silica-rich groundwater fills cavities in volcanic rock, depositing concentric layers over millions of years, commonly during the Cenozoic or older volcanic episodes. Dyeing and polishing are modern human processing rather than natural formation.

Uses & applications

Used for jewelry, beads, cabochons, carvings, and ornamental objects; common dyed pieces have modest decorative value.

Geological facts

Agate is a variety of chalcedony composed of fibrous quartz and often tiny amounts of iron or other coloring impurities. Dye penetrates pores and fractures, producing colors rarely found naturally—especially intense blue or neon green.

Field identification & locations

Identify by its glassy/waxy polish, very high durability, translucent edges, and curved internal banding; a steel file should not easily scratch it. Common sources include Brazil, Uruguay, India, Mexico, and Madagascar; the exact locality cannot be determined from the image.