mineral

Moss Agate

Chalcedony (Silicon Dioxide) with inclusions - SiO2

Hardness: 6.5-7 (Mohs scale); Color: semi-transparent white with green, brown, or black dendritic 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 April 4, 2026More mineral →

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Physical properties

Formation & geological history

Formed through the cooling of silica-rich hydrothermal fluids in cavities of igneous rocks. The characteristic green 'moss' patterns are caused by chemical impurities of manganese or iron oxides that crystallize into dendritic patterns during formation.

Uses & applications

Primarily used for lapidary work, jewelry (cabochons, beads, rings), decorative carvings, and as a popular specimen for metaphysical collectors.

Geological facts

Despite its name, Moss Agate contains no organic plant matter; the 'moss' is purely mineral growth. It was historically known as the 'Gardener's Stone' as it was believed to ensure a bountiful harvest.

Field identification & locations

Identify in the field by its translucency (light passes through the white/clear parts) and the distinctive plant-like filaments inside. Commonly found in India, Brazil, Uruguay, central Europe, and the western United States (Montana).

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