gemstone

Tree Agate

Chalcedony (SiO2)

Hardness of 6.5 to 7 on the Mohs scale, milky white to clear color with distinct green dendritic or fern-like inclusions, vitreous to waxy luster, microcrystalline crystal structure, conchoidal fracture, and specific gravity of 2.58 to 2.64.

Identified August 1, 2026More gemstone →

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Physical properties

Formation & geological history

Formed in hydrothermal veins or cavities of volcanic and metamorphic rocks where silica-rich groundwater rich in iron and manganese deposits mineral solutions over millions of years.

Uses & applications

Commonly used in lapidary arts, tumbled stones, wire-wrapped jewelry, carvings, and as a popular collector's mineral specimen.

Geological facts

Despite its name, tree agate is not made of fossilized tree material (like petrified wood), but rather gets its appearance from mineral impurities like chromium or iron that create the plant-like dendritic patterns.

Field identification & locations

Easily identified by its opaque to translucent white background contrasted with striking green dendritic patterns. Found worldwide including India, Brazil, the USA, and Australia.