sedimentary
Green Moss Agate
Silicon Dioxide (SiO2) with inclusions of hornblende or chlorite
Hardness: 6.5–7 on Mohs scale; Color: Clear to milky white with green dendritic (plant-like) inclusions; Luster: Vitreous to waxy; Crystal structure: Trigonal/Microcrystalline; Cleavage: None (conchoidal fracture); Specific gravity: 2.58–2.64.
- Hardness
- 6
- Luster
- Vitreous to waxy
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Physical properties
Hardness: 6.5–7 on Mohs scale; Color: Clear to milky white with green dendritic (plant-like) inclusions; Luster: Vitreous to waxy; Crystal structure: Trigonal/Microcrystalline; Cleavage: None (conchoidal fracture); Specific gravity: 2.58–2.64.
Formation & geological history
Formed through the deposition of silica in volcanic rock cavities or sedimentary fissures over millions of years. The moss-like green patterns are caused by the presence of manganese or iron oxide minerals during the crystallization process. It is found in many geological ages, particularly associated with Cenozoic volcanic activity.
Uses & applications
Primarily used in jewelry (cabochons, beads, pendants), ornamental carvings, and as a popular specimen for crystal collectors. It is historically known as a stone for gardeners and agriculture.
Geological facts
Despite its name, Moss Agate does not contain organic plant matter; the 'moss' is actually mineral inclusions. In the 18th century, it was known as a 'stone of fortune' in Europe and was often placed around the house to bring wealth.
Field identification & locations
Identify in the field by its translucency when held to light, revealing internal green branching filaments. It is commonly found in India, Brazil, Uruguay, central Europe, and the western United States (Montana). Collectors should look for high contrast between the clear chalcedony and deep green patterns.
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