Cute thumber. Unusual locality, but celestine is just so common. I might put $15 on it, and ten bucks of that price is for the extinct classic locality. Maybe more to a real TN nut or Illinois specialist, but that's a tough sell.
I agree with Tim. The state of the terminations is critical. If one or more of the terminations are damaged, contacted, or otherwise incomplete the max price is ten dollars. If all terminations are pristine add five to eight dollars.