Where is Wonderstone found?
Rhyolite (flow-banded)
Got a photo? Identify rocks instantly with the Rockby app
Open the appWonderstone 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 Wonderstone
South Africa (Ottosdal, North West Province)
The most famous and commercially significant source of Wonderstone, particularly the 'Ottosdal Wonderstone'. This deposit is part of the Ventersdorp Supergroup and is Proterozoic in age. It is renowned for its exceptional purity and homogeneity.
United States (various locations)
Rhyolite with flow banding can be found in numerous volcanic regions, including the western United States (e.g., Yellowstone National Park, Nevada, Arizona, New Mexico, California). While not always marketed as 'Wonderstone', these are geologically similar flow-banded rhyolites.
Australia
Flow-banded rhyolites occur in various volcanic provinces across Australia, particularly in ancient cratonic areas and younger volcanic fields.
New Zealand
Known for its extensive rhyolitic volcanism, New Zealand has numerous occurrences of flow-banded rhyolite, especially in the North Island's Taupo Volcanic Zone.
Collecting tips
- Look for Volcanic Terrains. Focus your search on areas with known felsic volcanic activity, especially ancient lava flows or caldera margins. Outcrops may show distinct banding.
- Examine Outcrop Textures. Look for rocks with fine-grained textures and clear, often wavy or contorted, parallel bands. Weathered surfaces might highlight the banding more effectively.
- Check for Conchoidal Fracture. Freshly broken surfaces of Wonderstone often exhibit a conchoidal to sub-conchoidal fracture, similar to obsidian or chert, due to its fine-grained nature.
- Consider Associated Minerals. Wonderstone may be found alongside other volcanic rocks like obsidian, pumice, or other types of rhyolite, as well as volcanic ash deposits.
Quick Check
- Color:
- Variable, often banded (gray, brown, red, purple, cream)
- Luster:
- Dull to waxy/vitreous
- Streak:
- White (due to high silica content)
Explore Wonderstone
Identify rocks anywhere
Free on iOS, Android, and Web. Photo identification, full database, and your personal collection.