mineral

Moss Agate

Silicon Dioxide (SiO2) with Manganese or Iron Oxide inclusions

Hardness: 6.5-7 (Mohs); Color: White to translucent with green, moss-like inclusions; Luster: Vitreous to waxy; Crystal Structure: Hexagonal (Trigonal); Cleavage: None; Specific Gravity: 2.58-2.64

Hardness: 6
Color: White to translucent with green, moss-like inclusions
Luster: Vitreous to waxy

Identified May 7, 2026More mineral →

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Physical properties

Hardness: 6.5-7 (Mohs); Color: White to translucent with green, moss-like inclusions; Luster: Vitreous to waxy; Crystal Structure: Hexagonal (Trigonal); Cleavage: None; Specific Gravity: 2.58-2.64

Formation & geological history

Found in various geological environments, it forms through the deposition of silica from groundwater into cavities in igneous rocks. The 'moss' represents dendrite-like inclusions of manganese, iron, or chlorite rather than organic material.

Uses & applications

Primarily used for lapidary work, jewelry (cabochons, beads), decorative carvings, and as a popular collector specimen due to its unique patterns.

Geological facts

Despite its name, Moss Agate does not contain actual organic moss. Its dendrites are strictly mineral growth. It was historically called 'Mocha Stone' after the city of Mocha in Yemen.

Field identification & locations

Identify by its characteristic green branching patterns against a clear or milky white chalcedony background. It is commonly found in India, Brazil, Uruguay, and the United States (notably Montana).

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