Where is Dendritic Opal found?
SiO2·nH2O
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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
Turkey
Known for producing high-quality dendritic opal, particularly from the Eskisehir region.
United States
Various localities, including Nevada, Oregon, Idaho, and Arizona, yield dendritic opal, often associated with volcanic activity.
Australia
While famous for precious opal, common opal with dendritic inclusions can also be found in some regions.
Mexico
Some deposits of common opal with dendritic patterns have been reported.
Brazil
Occurrences of dendritic opal are known, often associated with agate and chalcedony deposits.
Collecting tips
- Look for Silica-Rich Environments. Search in areas with past or present volcanic activity, hot springs, or sedimentary formations where silica-rich fluids would have been present.
- Examine Voids and Fractures. Dendritic opal often forms in cavities, geodes, or fissures within host rocks. Look for milky or translucent material filling these spaces.
- Identify Dendritic Patterns. The key identifying feature is the fern-like or tree-like inclusions. These are usually dark against a lighter background.
- Check for Hardness. Opal is relatively soft (5.5-6.5 on Mohs scale), so it can be scratched by quartz. This helps differentiate it from dendritic agate.
Quick Check
- Color:
- White, gray, cream, or colorless base with black/brown/reddish-brown dendritic patterns.
- Luster:
- Vitreous to waxy.
- Streak:
- White.
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