mineral

Dendritic Opal

Hydrated Silica (SiO2·nH2O) with Manganese or Iron Oxide inclusions

Hardness: 5.5-6.5 on Mohs scale; Color: Milky white to grey with black or brown tree-like patterns; Luster: Vitreous to waxy; Crystal structure: Amorphous; Cleavage: None (conchoidal fracture); Specific Gravity: 1.9-2.3

Hardness: 5
Color: Milky white to grey with black or brown tree-like patterns
Luster: Vitreous to waxy

Identified May 9, 2026More mineral →

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Physical properties

Formation & geological history

Formed at low temperatures from silica-rich waters that seep into crevices in host rocks. The 'dendrites' are formed by the crystallization of manganese or iron oxides during the opal's formation. Primarily found in Madagascar, Australia, and New Mexico.

Uses & applications

Used primarily as a gemstone in jewelry (cabochons, pendants), ornamental carvings, and widely used in metaphysical or collector markets.

Geological facts

Also known as 'Merlinite' in metaphysical circles, the name 'dendritic' comes from the Greek word 'dendron' meaning tree, referring to the branching moss-like inclusions that are mistaken for fossilized plants.

Field identification & locations

Identify by its characteristic moss-like or tree-like branching patterns (dendrites) inside a translucent to opaque white or grey base. It lacks the internal fire (opalescence) of precious opal. Common in areas with volcanic activity or hydrothermal deposition.

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