Dendritic Agate

Physical Properties

Hardness: 6.5-7 (Mohs scale); Color: Colorless, white, or gray with black to brown inclusions; Luster: Vitreous to waxy; Crystal Structure: Trigonal (microcrystalline); Cleavage: None/Conchoidal fracture; Specific gravity: 2.58-2.64

Formation & Geological History

Formed from silica-rich groundwater filling cavities in volcanic rocks. The 'tree-like' patterns (dendrites) are created when manganese and iron oxides manganese filter into the cracks of the stone as it forms.

Uses & Applications

Primarily used in jewelry (cabochons), ornamental carvings, and widely collected by mineral enthusiasts as meditation stones.

Geological Facts

Despite its name, it is technically an 'agate' only in the trade sense; gemologically, agates must feature banding, while dendritic agate is a translucent to opaque variety of chalcedony.

Field Identification & Locations

Identify in the field by its characteristic mossy or fern-like patterns against a translucent base. Common locations include Brazil, India, Madagascar, and parts of the United States like Montana.

Identified on: 4/22/2026

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