mineral

Moss Agate

Silicon Dioxide with inclusions (SiO2 + Mn/Fe oxides)

Hardness: 6.5-7 (Mohs); Color: Clear to milky white with green, black, or brown dendritic inclusions; Luster: Vitreous; Crystal Structure: Hexagonal (cryptocrystalline); Specific Gravity: 2.58-2.64

Hardness: 6
Luster: Vitreous

Identified May 10, 2026More mineral →

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Physical properties

Hardness: 6.5-7 (Mohs); Color: Clear to milky white with green, black, or brown dendritic inclusions; Luster: Vitreous; Crystal Structure: Hexagonal (cryptocrystalline); Specific Gravity: 2.58-2.64

Formation & geological history

Formed from the deposition of silica-rich groundwater in cavities of igneous rocks. The 'moss' patterns are caused by dendritic inclusions of manganese or iron oxides during formation.

Uses & applications

Primarily used in jewelry (cabochons, beads, rings), ornamental carvings, crystal healing practices, and as collector specimens.

Geological facts

Despite its name, Moss Agate does not contain organic matter; the plant-like patterns are purely mineral growth. It is often associated with agriculture and has been historically called the 'gardener's stone'.

Field identification & locations

Identify by looking for translucent chalcedony containing dark green or black branching, moss-like inclusions. Often found in India, Brazil, Uruguay, and the western United States (Montana).

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