mineral
Dendritic Opal (Merlinite)
Hydrated Silica with Manganese/Iron oxide inclusions (SiO2·nH2O)
AI-generated identification · may be incorrectHardness: 5.5-6.5 (Mohs scale); Color: Creamy white or milky base with black or green tree-like inclusions; Luster: Vitreous to waxy; Crystal Structure: Amorphous; Cleavage: None
- Hardness
- 5
- Luster
- Vitreous to waxy
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Physical properties
Hardness: 5.5-6.5 (Mohs scale); Color: Creamy white or milky base with black or green tree-like inclusions; Luster: Vitreous to waxy; Crystal Structure: Amorphous; Cleavage: None
Formation & geological history
Formed as silica-rich water seeps into cracks and cavities in volcanic rocks. The 'branching' patterns are created by the crystallization of manganese or iron oxides during the cooling process.
Uses & applications
Predominantly used as a gemstone for jewelry (cabochons), lapidary carvings, and in metaphysical collections for its aesthetic 'landscape' appearance.
Geological facts
Although called 'opal', dendritic opal is technically a form of common opal that does not exhibit 'play-of-color'. The black patterns are often mistaken for fossilized plants (ferns), but they are strictly mineral growths.
Field identification & locations
Identified in the field by its distinctive moss-like or tree-like dark patterns against a white opaque background. Commonly found in Australia, Mexico, and Madagascar. Collectors look for high contrast and intact 'forest' patterns.
