mineral
Dendritic Agate / Moss Agate
Silicon Dioxide (SiO2) with Manganese/Iron oxide inclusions
AI-generated identification · may be incorrectHardness: 6.5-7 (Mohs); Color: Translucent grey to white with dark inclusions; Luster: Vitreous to waxy; Crystal Structure: Trigonal (microcrystalline); Cleavage: None (conchoidal fracture); Specific Gravity: 2.58–2.64
- Hardness
- 6
- Color
- Translucent grey to white with dark inclusions
- Luster
- Vitreous to waxy
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Physical properties
Hardness: 6.5-7 (Mohs); Color: Translucent grey to white with dark inclusions; Luster: Vitreous to waxy; Crystal Structure: Trigonal (microcrystalline); Cleavage: None (conchoidal fracture); Specific Gravity: 2.58–2.64
Formation & geological history
Formed in cavities within volcanic or sedimentary rocks through the deposition of silica-rich groundwater. The tree-like or spotted inclusions are formed by the infiltration of manganese or iron oxides during crystallization.
Uses & applications
Used primarily for jewelry making (cabochons), collection, decorative carvings, and alternative healing practices.
Geological facts
Despite the name, moss or dendritic agates do not contain organic matter; the 'plant' patterns are purely mineral growth called dendrites. They were historically known as 'The Gardner's Stone' for their alleged ability to ensure a good harvest.
Field identification & locations
Identify in the field by its translucency (light passes through edges) and the presence of internal moss-like or speckled patterns that do not rub off. Common in riverbeds and volcanic regions like those in Montana, USA, or India.
