I found this in or along a river bed either near the Van Duzen County Park, or somewhere on the Mad River near the hatchery or down stream at one of the many swimming spots. It fits perfectly in one's hand, and is nearly perfectly flat on one side.
Nokta FoRs Gold, a Gold Cube, 2 Keene Sluices and Lord only knows how many pans....not to mention a load of other gear my wife still doesn't know about!