mineral

Moss Agate / Chalcedony

Silicon Dioxide (SiO2)

Hardness: 6.5-7 (Mohs scale). Color: Translucent to gray-white with green/brown filament inclusions. Luster: Vitreous to waxy. Crystal Structure: Trigonal (cryptocrystalline). Cleavage: None. Specific Gravity: 2.58–2.64.

Hardness: 6
Luster: Vitreous to waxy

Identified March 26, 2026More mineral →

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Physical properties

Formation & geological history

Formed from the deposition of silica-rich groundwater within volcanic rock cavities. The 'moss' appearance is caused by impurities of manganese and iron oxides that form dendritic patterns. Typically found in Cenozoic era volcanic formations.

Uses & applications

Predominantly used as a gemstone for jewelry (cabochons, beads), decorative carvings, and as a popular specimen for crystal healing collectors or metaphysical use.

Geological facts

Despite its name, Moss Agate contains no organic plant material; the patterns are strictly mineral dendrites. It was historically called the 'Gardener's Stone' and was believed to ensure a bountiful harvest.

Field identification & locations

Identify in the field by its translucency and characteristic branch-like inclusions. Commonly found in riverbeds or volcanic areas. Found globally, with significant deposits in India, Brazil, Uruguay, and the United States (Montana/Oregon).