mineral

Dendritic Agate

Silicon Dioxide (SiO2) with inclusions of manganese or iron oxides

Hardness: 6.5–7 (Mohs scale), Color: Translucent white to milky-gray with brown/orange tree-like inclusions, Luster: Vitreous to waxy, Crystal Structure: Trigonal (Microcrystalline), Cleavage: None (Conchoidal fracture), Specific Gravity: 2.60–2.65

Hardness: 6

Identified March 24, 2026More mineral →

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Physical properties

Formation & geological history

Formed when mineral-rich water (carrying manganese or iron) seeps into cracks in chalcedony/agate. The minerals crystallize into branching 'dendrites' as the water evaporates. Found in volcanic or metamorphic host rocks.

Uses & applications

Primarily used in jewelry (cabochons, rings, pendants), ornamental carvings, and as a popular specimen for collectors who value unique 'landscape' patterns.

Geological facts

Although called 'agate,' it is technically a dendritic chalcedony because it lacks the concentric banding typical of true agates. The word 'dendritic' comes from the Greek 'dendron,' meaning tree.

Field identification & locations

Identify by looking for fern-like or tree-like branching patterns inside a translucent or milky stone. Common locations include Brazil, India, Madagascar, and the USA (Montana). Collectors look for high translucency and clear, artistic patterns.

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