Where is Dendritic Opal found?
Opal (SiO2·nH2O) with manganese dendrites
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Open the appDendritic Opal occurs in specific geological environments. Knowing where to look, and in what kind of rock, is the difference between going home empty-handed and finding a great specimen.
Where to find Dendritic Opal
Indonesia
Known for producing high-quality dendritic opals, often with clear base material and well-defined black dendrites.
Turkey
Sources of dendritic opal, sometimes referred to as 'Turkish Dendritic Opal'.
USA (Nevada, Oregon, Idaho)
Various opal deposits in the western United States can yield dendritic opal, particularly common opal varieties.
Australia
While famous for precious opal, common opal with dendritic inclusions can also be found in some localities.
Collecting tips
- Look for Silica-Rich Environments. Search in areas with volcanic activity, hot springs, or sedimentary deposits where silica precipitation is common. Opal often forms in association with volcanic ash beds or in weathered igneous rocks.
- Examine Rock Cavities and Veins. Dendritic opal typically forms in voids, fissures, and cracks within host rocks. Look for nodules or vein fillings.
- Identify Manganese Staining. The presence of black or dark brown manganese staining on surrounding rocks can be an indicator of the potential for dendritic inclusions in opal.
- Check for Waxy Luster. Opal, including dendritic opal, often exhibits a characteristic waxy to vitreous luster, which can help distinguish it from other minerals.
Quick Check
- Color:
- White, gray, cream, or light brown with black/dark brown fern-like patterns.
- Luster:
- Vitreous to waxy to resinous.
- Streak:
- White (for the opal matrix); the dendrites themselves are too fine to produce a distinct streak on their own, but the overall streak would be that of the opal.
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