mineral

Moss Agate

Chalcedony (Silicon Dioxide, SiO2) with dendritic inclusions

Hardness: 6.5–7; Color: Clear or milky white base with green, moss-like inclusions; Luster: Vitreous to waxy; Crystal structure: Trigonal/Microcrystalline; Cleavage: None/Conchoidal fracture; Specific gravity: 2.58–2.64

Hardness: 6
Color: Clear or milky white base with green, moss-like inclusions
Luster: Vitreous to waxy

Identified March 26, 2026More mineral →

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Physical properties

Formation & geological history

Formed through the deposition of silica-rich groundwater in cavities of igneous rocks, where filament-like inclusions of manganese or iron oxides (macerated minerals) grow into the characteristic moss patterns.

Uses & applications

Primarily used in jewelry (cabochons, beads), decorative carvings, and as a popular specimen for crystal collecting and metaphysical purposes.

Geological facts

Despite its name, Moss Agate does not contain organic matter or real moss; the 'moss' is actually mineral dendrites. It was historically known as the 'Mocha Stone' due to its trade through the Arabian port of Mocha.

Field identification & locations

Identify by its translucent body combined with branching, dark green filament inclusions. Common locations include India, Brazil, Uruguay, and the United States (specifically the Yellowstone River area). Collectors should look for high translucency and 'vibrant' moss patterns.

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