mineral

Dendritic Agate

Silicon Dioxide (SiO2) with Manganese/Iron oxide inclusions

AI-generated identification · may be incorrect

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

Hardness: 6

Identified June 19, 2026More mineral →

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Physical properties

Formation & geological history

Formed through the deposition of silica from groundwater in cavities of igneous rocks. The dendritic patterns are created when manganese or iron oxides seep into cracks and crystallize in branching patterns during or after the agate formation.

Uses & applications

Primarily used in jewelry (cabochons), lapidary art, and as metaphysical or collector specimens. Also historically used for amulets and seals.

Geological facts

Despite the name, dendritic agate is often technically a chalcedony rather than a true agate because it typically lacks the concentric banding characteristic of Agate. The 'tree-like' patterns are purely mineral and are not fossilized plants.

Field identification & locations

Identify by its translucent body and distinctive fern-like or moss-like black/brown inclusions. Found commonly in Brazil, India, Madagascar, and the USA (notably Montana and Oregon). Collectors look for high contrast and clear patterns.