sedimentary

Merlinite (dendritic opal)

Common opal (hydrated amorphous silica, SiO₂·nH₂O) with dark manganese-oxide dendrites; the trade name “merlinite” is also applied to other patterned stones.

AI-generated identification · may be incorrect

Polished pendant with a gray-white body and black branching patterns, vitreous to waxy luster, and no visible crystal structure. Opal is about 5.5–6.5 on the Mohs scale; hardness and density vary with impurities.

Identified September 29, 2026More sedimentary →

Explore Merlinite (dendritic opal) in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

At a glance

Common name: Merlinite (dendritic opal)
Scientific name: Common opal (hydrated amorphous silica, SiO₂·nH₂O) with dark manganese-oxide dendrites; the trade name “merlinite” is also applied to other patterned stones.
Category: sedimentary
Identified: September 29, 2026
Method: Standard

AI Estimated Value

About $10–$50 for a typical small pendant; higher-quality stones or precious-metal settings may cost more.

Not an official valuation

AI estimate for general interest only — not an appraisal. Actual value depends on condition, provenance, and market demand. Verify with a professional before buying, selling, or insuring.

This identification was generated by AI and may contain errors. Verify important details before relying on them — and never use an AI result to judge whether a specimen is safe to handle. Read the full disclaimer

Physical properties

Formation & geological history

Silica-rich water deposited opal in rock cavities or fractures; manganese oxides formed the dark dendritic markings. These deposits are generally geologically young, though exact age and locality cannot be determined from the photo.

Uses & applications

Used mainly for cabochons, pendants, and decorative objects.

Geological facts

Dendrites are mineral growth patterns, not fossils or plant remains. “Merlinite” is a commercial name rather than a consistently defined mineral species.

Field identification & locations

The teardrop cabochon and metal bail indicate a finished jewelry piece; the image alone cannot confirm the stone or its locality. Look for natural branching inclusions and avoid relying on the trade name alone.