mineral

Moss Agate

Silicon Dioxide with inclusions (SiO2)

Hardness: 6.5-7 on the Mohs scale. Color: Clear to milky white base with green, brown, or black dendritic inclusions. Luster: Vitreous to waxy. Crystal Structure: Hexagonal (cryptocrystalline). Cleavage: None. Specific Gravity: 2.58-2.64.

Hardness: 6
Luster: Vitreous to waxy

Identified May 20, 2026More mineral →

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Physical properties

Formation & geological history

Formed from the deposition of silica from groundwater in the cavities of igneous rocks. The 'moss' appearance is caused by manganese or iron oxide inclusions during the cooling process. Geological age varies by deposit location.

Uses & applications

Primarily used for ornamental purposes, including jewelry (cabochons, beads), decorative carvings, and polished spheres for mineral collectors.

Geological facts

Despite its name, Moss Agate does not contain organic matter; the plant-like patterns are strictly mineral dendrites. It was historically known as a 'gardener's stone' believed to ensure a bountiful harvest.

Field identification & locations

Identify by its translucent chalcedony body and characteristic branching (dendritic) inclusions that resemble moss or foliage. Commonly found in India, Brazil, Uruguay, central Europe, and the western United States.