mineral

Moss Agate

Silicon Dioxide with inclusions (SiO2 + impurities)

Hardness: 6.5–7 (Mohs scale); Color: Clear to milky white with green, dendritic (moss-like) inclusions; Luster: Vitreous to waxy; Crystal structure: Trigonal (microcrystalline); Cleavage: None (conchoidal fracture); Specific gravity: 2.58–2.64

Hardness: 6
Luster: Vitreous to waxy

Identified March 20, 2026More mineral →

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Physical properties

Formation & geological history

Formed through the deposition of silica-rich groundwater in cavities or cracks of igneous rocks. The dendritic green patterns are caused by inclusions of manganese or iron oxides, particularly hornblende or chlorite. Specimen ages vary greatly depending on the host rock, often spanning millions of years.

Uses & applications

Primarily used in jewelry for cabochons, beads, and pendants. Also highly valued in the metaphysical and collecting communities as a 'stone of agriculture' and gardener's talisman.

Geological facts

Despite its name, moss agate is not a true form of agate because it lacks the concentric banding typically required for that classification; it is technically a variety of chalcedony. It was historically believed to ensure a bountiful harvest and was often placed in the soil of crops.

Field identification & locations

Identify in the field by its translucent body paired with dark green, organic-looking branched inclusions. Common locations include India, Brazil, Uruguay, and the United States (specifically the Yellowstone River area in Montana). Collectors should look for high transparency in the base stone to better highlight the internal 'moss'.

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