mineral

Moss Agate

Silicon Dioxide (SiO2) with Manganese/Iron Oxide inclusions

Hardness: 6.5-7 on Mohs scale; Color: Translucent chalcedony with dark green, black, or brown moss-like inclusions; Luster: Vitreous to waxy; Crystal Structure: Trigonal/Microcrystalline; Cleavage: None; Specific Gravity: 2.58-2.64.

Hardness: 6
Luster: Vitreous to waxy

Identified July 27, 2026More mineral →

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Physical properties

Formation & geological history

Formed in volcanic rocks, where silica-rich hydrothermal fluids precipitate inside basalt or lava cavities. Manganese and iron oxides grow into branching, dendritic pattern inclusions resembling moss or ferns.

Uses & applications

Popular as a gemstone for jewelry (cabochons, beads, rings), lapidary arts, decorative carvings, and metaphysical/healing crystal collections.

Geological facts

Despite its name, moss agate does not contain organic plant matter or real moss; the 'moss' is actually mineral inclusions such as hornblende, chlorite, or manganese oxides forming dendritic branching networks.

Field identification & locations

Identify in the field by checking light transparency: translucent chalcedony quartz matrix containing dark green or black fern-like structures. Found worldwide, notably in India, Brazil, Montana (USA), and Madagascar.

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