mineral

Dendritic Agate

Silicon Dioxide (SiO2) with manganese/iron inclusions

Hardness: 6.5–7 on Mohs scale; Color: Translucent white to grey with dark branching inclusions; Luster: Vitreous to waxy; Crystal structure: Trigonal/Microcrystalline; Cleavage: None; Specific gravity: 2.58–2.64

Hardness: 6
Color: Translucent white to grey with dark branching inclusions
Luster: Vitreous to waxy

Identified March 28, 2026More mineral →

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Physical properties

Formation & geological history

Formed through the deposition of silica-rich groundwater in cavities of igneous or sedimentary rocks. The dendritic 'tree-like' patterns are formed by manganese and iron oxides crystallizing in a branching pattern through microscopic cracks.

Uses & applications

Primarily used in jewelry (cabochons), lapidary arts, and as collector specimens. Often used in rings, pendants, and decorative carvings due to its unique patterns.

Geological facts

Despite being called an 'agate,' it technically lacks the characteristic banding seen in true agates; it is botanically named for its moss-like or tree-like inclusions. It was highly prized in ancient times as a talisman for a plentiful harvest.

Field identification & locations

Identify by its translucent body combined with dark, fern-like internal patterns. Found commonly in Brazil, India, Madagascar, and the USA (Montana/Oregon). Collectors look for high contrast and clear background stone.

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