mineral

Tree Agate (also known as Dendritic Agate)

Silicon Dioxide with inclusions (SiO2 + Mn/Fe)

Hardness: 6.5-7 (Mohs scale); Color: White, grayish, or clear base with green branching inclusions; Luster: Vitreous to waxy; Crystal Structure: Hexagonal (trigonal); Cleavage: None; Specific Gravity: 2.6-2.65

Hardness: 6
Luster: Vitreous to waxy

Identified March 28, 2026More mineral →

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Physical properties

Formation & geological history

Formed when water rich in manganese and iron oxides flows through cracks in volcanic rock or limestone, depositing minerals that crystallize in dendritic patterns. Most deposits date from the Tertiary period.

Uses & applications

Primarily used for ornamental purposes, tumbling, jewelry cabochons, and metaphysical collecting.

Geological facts

Despite its name, the inclusions are not organic plant matter but are mineral deposits of manganese or iron that grow in a branching pattern similar to trees or ferns.

Field identification & locations

Identify by its characteristic 'mossy' or 'forest' green dendritic patterns on a white background. Frequently found in Brazil, India, and the USA (notably Montana). Collectors should look for high contrast between the white base and deep green patterns.

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