mineral

Moss Agate

Silicon dioxide (SiO2) with inclusions of hornblende or chlorite

Hardness: 6.5-7 (Mohs). Color: Clear to milky white with green dendritic inclusions. Luster: Vitreous to waxy. Structure: Trigonal (cryptocrystalline). No cleavage. Specific gravity: 2.58-2.64.

Hardness: 6
Color: Clear to milky white with green dendritic inclusions
Luster: Vitreous to waxy

Identified April 4, 2026More mineral →

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Physical properties

Hardness: 6.5-7 (Mohs). Color: Clear to milky white with green dendritic inclusions. Luster: Vitreous to waxy. Structure: Trigonal (cryptocrystalline). No cleavage. 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 manganese or iron oxide inclusions during formation, creating dendritic patterns.

Uses & applications

Used primarily in lapidary arts, jewelry (cabochons, beads), tumbled stones for collectors, and ornamental carvings.

Geological facts

Despite its name, Moss Agate is not technically a true agate because it lacks concentric banding; it is a chalcedony with dendritic inclusions. It was historically known as the 'Gardener's Stone'.

Field identification & locations

Identify by looking for green, plant-like branching patterns inside a translucent quartz base. Commonly found in India, Brazil, Uruguay, and the western United States (Montana).

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