gemstone

Dendritic Agate

Silicon Dioxide with Iron or Manganese Oxides (SiO2)

Hardness: 6.5-7 on the Mohs scale. Color: White, grey, or colorless with dark brown to black fern-like or tree-like inclusions (dendrites). Luster: Vitreous to waxy. Crystal structure: Trigonal (microcrystalline quartz/chalcedony). Cleavage: None.

Hardness: 6
Luster: Vitreous to waxy

Identified July 28, 2026More gemstone →

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Physical properties

Formation & geological history

Formed in cavities and fissures of volcanic or metamorphic rocks through the deposition of silica-rich groundwater solutions carrying iron or manganese oxides, often over millions of years.

Uses & applications

Used primarily as a gemstone for cabochons, jewelry, carvings, and decorative ornamental items, as well as valued by collectors.

Geological facts

Despite the name, dendritic agates do not always possess the concentric banding typical of true agates, but they are categorized as such due to their chalcedony base and similar formation environments.

Field identification & locations

Easily identified by its distinctive tree-like or branching dendritic patterns trapped within a translucent to opaque quartz matrix. Found globally in locations such as India, Brazil, the USA, and Madagascar.

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