gemstone

Green Chalcedony (Batu Akik)

Silicon Dioxide (SiO2)

Hardness of 6.5 to 7 on the Mohs scale, vibrant green color (often artificially enhanced or naturally colored by trace minerals like chromium or nickel), waxy to vitreous luster, microcrystalline (cryptocrystalline) quartz structure, conchoidal fracture with no cleavage, specific gravity of 2.58-2.62.

Identified August 7, 2026More gemstone →

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Physical properties

Formation & geological history

Formed in low-temperature environments through the deposition of silica-rich waters in rock cavities, fractures, or sedimentary environments. Given the location context near West Java, Indonesia (6.6°S, 106.8°E), such chalcedony and agate rings (locally known as Batu Akik) are culturally very common and frequently sourced from volcanic-hosted hydrothermal deposits in the region.

Uses & applications

Primarily used in jewelry, cabochons, signet rings, and as a popular collector's item or talisman in Southeast Asia.

Geological facts

Chalcedony has been used for thousands of years in the creation of intaglios, seals, and ornamental jewelry. In Indonesia, green chalcedony and similar 'Batu Akik' varieties experienced a massive cultural collecting boom.

Field identification & locations

Can be identified by its smooth cabochon polish, hardness that scratches glass, waxy luster, and uniform or slightly banded translucent green body. Common in gemstone markets throughout Indonesia.

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