Moss Agate

Physical Properties

Hardness: 6.5-7 (Mohs). Color: Clear to milky white with green, black, or red dendritic inclusions. Luster: Vitreous to waxy. Crystal Structure: Trigonal (microcrystalline). Cleavage: None. SG: 2.58-2.64.

Formation & Geological History

Formed from the deposition of silica-rich groundwater in the cavities of igneous rocks. The 'moss' patterns are caused by dendritic inclusions of metal oxides that crystallize as the silica solidifies.

Uses & Applications

Primarily used in jewelry (cabochons, beads), ornamental carvings, and as a popular lapidary material for collectors.

Geological Facts

Despite its name, Moss Agate does not contain organic matter or moss. It was historically regarded as a stone of agriculture, and gardeners believed it would ensure a bountiful harvest.

Field Identification & Locations

Identify by looking for translucent to transparent chalcedony with branch-like, mossy, or filamentous patterns. Commonly found in India, Brazil, Uruguay, and the United States (Montana).

Identified on: 4/18/2026

Mode: Standard