sedimentary
Tree Agate
Dendritic Chalcedony (SiO2)
Hardness: 6.5-7 (Mohs); Color: Green and white; Luster: Vitreous to waxy; Crystal Structure: Trigonal (Microcrystalline); Cleavage: None; Specific Gravity: 2.58-2.64
- Hardness
- 6
- Color
- Green and white
- Luster
- Vitreous to waxy
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Physical properties
Hardness: 6.5-7 (Mohs); Color: Green and white; Luster: Vitreous to waxy; Crystal Structure: Trigonal (Microcrystalline); Cleavage: None; Specific Gravity: 2.58-2.64
Formation & geological history
Formed via the accumulation of silica-rich water in volcanic rock cavities or sedimentary fissures, where manganese or iron oxides create dendritic patterns. Over millions of years, these minerals solidify into agate.
Uses & applications
Primarily used in jewelry (cabochons, beads), decorative carvings, and as a popular specimen for collectors and holistic practices.
Geological facts
Despite its name, the fern-like patterns (dendrites) are not fossilized plants but are mineral inclusions of iron or manganese that grew in branching patterns during formation.
Field identification & locations
Identify by its characteristic green spots or branching moss-like patterns against a white translucent or opaque background. Found frequently in India, Brazil, and the USA.
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