Winemaker Gustav Heineman discovered the largest geode, filled with celestine crystals and measuring over 10 meters across, on South Bass Island, Ohio, in 1897. The geode formed during the Silurian period, around 430 million years ago, when glaciers melted at the end of the last ice age. Lake Erie water seeped into anhydrite pockets, dissolving them and creating caves.
Related Posts
We can use drones to get inside and learn more about active, gassy volcanoes
An overhead shot of a volcano crater in east Java, Indonesia. (Shutterstock) Fiona D’Arcy, McGill University Volcanic eruptions…
The Mystery of Zabargad Island
Discover how the mysterious island of Zabargad, in the Red Sea, came to be, its significance in ancient…
Solar geoengineering might work, but local temperatures could keep rising for years
Some areas wouldn’t see immediate effects, and there could be serious consequences. Buda Mendes/Getty Images Patrick W. Keys,…
The Science of Rivers
For being surface features of the Earth that seem to have always been there since the dawn of…