sedimentary
Tree Agate
Silicon Dioxide (SiO2) with Chlorite inclusions
Hardness: 6.5-7 (Mohs); Color: White with dark green dendritic inclusions; Luster: Vitreous to waxy; Crystal structure: Trigonal (microcrystalline); Cleavage: None; Specific Gravity: 2.58–2.64
- Hardness
- 6
- Color
- White with dark green dendritic inclusions
- Luster
- Vitreous to waxy
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Physical properties
Hardness: 6.5-7 (Mohs); Color: White with dark green dendritic inclusions; Luster: Vitreous to waxy; Crystal structure: Trigonal (microcrystalline); Cleavage: None; Specific Gravity: 2.58–2.64
Formation & geological history
Formed in volcanic rock cavities where silica-rich groundwater deposits layers of chalcedony. The 'tree-like' patterns are formed by dendritic inclusions of manganese or iron silicates, specifically chlorite in this specimen.
Uses & applications
Predominantly used as a decorative gemstone for jewelry (cabochons, beads), metaphysical healing practices, and as tumbled pocket stones for collectors.
Geological facts
Also known as Dendritic Agate, though 'Tree Agate' specifically refers to the white and green variety. Ancient Greeks associated it with dryads and buried it in agricultural fields to ensure a bountiful harvest.
Field identification & locations
Identify by its opaque white base and mossy or branch-like green patterns. Unlike Moss Agate, Tree Agate is typically opaque rather than translucent. Commonly found in Brazil, India, and the USA (Montana).
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