Mineral

Tree Agate

Dendritic Agate (Silicon Dioxide, SiO2)

Hardness: 6.5–7 on Mohs scale; Color: White or grayish-translucent base with dark green, branch-like inclusions; Luster: Vitreous to waxy; Crystal structure: Hexagonal (Trigonal); Cleavage: None; Specific gravity: 2.58–2.64.

Hardness: 6
Luster: Vitreous to waxy

Identified March 25, 2026More mineral →

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Physical properties

Formation & geological history

Formed through the slow deposition of silica from groundwater in cavities of volcanic rock. The green 'tree' patterns are created by trace amounts of manganese or iron silicates that crystallize in dendritic patterns during formation.

Uses & applications

Primarily used in jewelry (cabochons, beads), decorative carvings, and as a popular specimen for rock collectors and metaphysical practitioners.

Geological facts

Despite being called 'Dendritic Agate,' it technically lacks the concentric banding of true agates and is scientifically a form of chalcedony. The name 'dendrite' comes from the Greek word 'dendron,' meaning tree.

Field identification & locations

Identify in the field by its distinct moss-like or branch-like green patterns against a milky white background. Often found in India, Brazil, and the USA (Montana/Wyoming). It is tough and takes a high polish.