mineral

Dendritic Agate

Silicon Dioxide (SiO2) with Manganese/Iron oxide inclusions

Hardness: 6.5-7 (Mohs), Color: Translucent white to gray with brown/black tree-like inclusions, Luster: Vitreous to waxy, Crystal Structure: Hexagonal (cryptocrystalline), Cleavage: None (conchoidal fracture), Specific Gravity: 2.58-2.64

Hardness: 6

Identified June 15, 2026More mineral →

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Physical properties

Formation & geological history

Formed when manganese or iron-rich mineral water flows through cracks in volcanic or sedimentary rocks, depositing tree-like patterns known as dendrites within chalcedony over millions of years.

Uses & applications

Primarily used in jewelry (cabochons), lapidary art, and as a collector's gemstone due to its unique patterns.

Geological facts

Despite the plant-like appearance, the inclusions are strictly mineral (typically manganese oxide) and contain no organic matter. Known as the 'stone of plenitude' in folklore.

Field identification & locations

Identify in the field by its distinct branch-like (dendritic) markings inside chalcedony. Commonly found in Brazil, India, Madagascar, and the USA (notably Montana and Oregon).

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