01/10/2026
Chalcedony nodules - UNLESS there is an actual agate feature, specifically fortification. Some varieties do have limited fortification, which means agate.
So how is it possible one could have fortification and the other doesn't? We can show you a specific native variety of these stones that have actual fortification. Spheroles/oolitic features do not count. Those can be a common feature of chert nodules, which these are actually in the same family. Sedimentary stones from a very widespread formation that covers multiple states in the Midwest. There are many varieties.
So by agate definition, two of the same thing and one can be sedimentary agate while the other is chalcedony. I will show you some cut examples of what I'm talking about this next week.
We don't make a habit of picking these stones up other than for educational purposes or to throw in the landscape.
