mineral

Moss Agate

Chalcedony (Silicon Dioxide, SiO2) with inclusions of Chlorite, Manganese, or Iron

Hardness: 6.5-7 (Mohs scale); Color: Clear to milky white with green, black, or brown moss-like inclusions; Luster: Vitreous to waxy; Crystal structure: Trigonal/Hexagonal (cryptocrystalline); Cleavage: None; Specific gravity: 2.58–2.64

Hardness: 6
Luster: Vitreous to waxy

Identified March 15, 2026More mineral →

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Physical properties

Formation & geological history

Formed from the deposition of silica in cavities of igneous rocks (usually volcanic). The 'moss' patterns are caused by the crystallization of mineral impurities like manganese or iron oxides within the cooling silica gel over millions of years.

Uses & applications

Primarily used as a semi-precious gemstone in jewelry (cabochons, beads, rings), as a decorative ornamental stone, and in metaphysical collecting.

Geological facts

Despite its name, Moss Agate is not a true organic moss; the patterns are purely mineral. It was historically considered a stone of agriculture, with gardeners once hanging it from trees to ensure a good harvest.

Field identification & locations

Identify by its translucent body combined with dendritic or moss-like green patterns. Found globally in locations like India, Brazil, Uruguay, and the USA (notably Montana). Collectors should look for high translucency and 'vibrant' branching patterns.

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