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
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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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