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Product Description
Agate Polished Collector Rock Waterline Idaho
This lovely gray agate nodule was cut in half and polished on one face. It also has a base cut on it to stand up.
This collectors agate came from a private collection and was self collected in the 1950's.
It is 3.56 inches tall, by 1.7 inches at its widest and 1.7 inches thick.
Found near Challis, a small town situated in central Idaho. This agate formed 52-39 million years ago in the Eocene. The Challis Volcanic Group covers approximately 25,000 square kilometers in Idaho, making it the largest of the Eocene volcanic fields.
This one shows fortification and waterline formation.
In contrast with fortification agates (or bands that wrap around the nodule), waterline agates develop "from the bottom, up," and layers of chalcedony are deposited in sequential events, distinctly in response to gravity. The waterline crystals likely formed as mineral-laden water seeped through the rock.
