mineral

Dendritic Opal

Hydrated Silica with Manganese inclusions (SiO2·nH2O)

Hardness: 5.5-6.5 (Mohs scale); Color: White, cream, or pale pink with black/brown tree-like patterns; Luster: Vitreous to waxy; Crystal structure: Amorphous; Cleavage: None; Specific Gravity: 1.9-2.3

Hardness: 5
Luster: Vitreous to waxy

Identified March 23, 2026More mineral →

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Physical properties

Formation & geological history

Formed through low-temperature deposition of silica-rich waters in fractures and cavities of various rocks (often igneous). The 'dendrites' are formed by manganese and iron oxides leaching into the cracks. Geological age varies by deposit location, commonly Cenozoic to recent.

Uses & applications

Primarily used in jewelry as cabochons, for lapidary carving, and as decorative metaphysical 'collector' stones.

Geological facts

Also known as 'Merlinite' in the metaphysical community. The name 'dendrite' comes from the Greek word 'dendron,' meaning tree, because the mineral inclusions resemble plant life or ferns.

Field identification & locations

Identify by its characteristic tree-like or moss-like inclusions (dendrites) against a milky white or cream background. Unlike common opal, it lacks 'play of color.' Common locations include Australia, Mexico, and Madagascar.

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