mineral

Moss Agate

Silicon Dioxide (SiO2) with inclusions of Manganese or Iron oxide

AI-generated identification · may be incorrect

Hardness: 6.5-7 on Mohs scale; Color: Clear to milky white with green, black, or red moss-like dendritic inclusions; Luster: Vitreous to waxy; Crystal Structure: Trigonal (cryptocrystalline); Cleavage: None (conchoidal fracture); Specific Gravity: 2.58-2.64

Hardness: 6
Luster: Vitreous to waxy

Identified March 15, 2026More mineral →

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Physical properties

Formation & geological history

Formed through the weathering of volcanic rocks. Silica-rich groundwater percolates through cavities in igneous rocks, depositing layers of chalcedony. The 'moss' patterns are formed by dendritic oxides of manganese or iron trapped within the cooling silica gel.

Uses & applications

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

Geological facts

Despite its name, Moss Agate does not contain organic matter or real moss; the patterns are purely mineral. It has been historically known as the 'Gardener's Stone' and was used in ancient amulets to ensure a bountiful harvest.

Field identification & locations

Identify by its characteristic branching, plant-like inclusions visible through a translucent or white chalcedony base. Commonly found in India, Brazil, Uruguay, and the western United States (Montana). Collectors look for high translucency and high-contrast, well-defined dendritic 'trees'.