Patina, patina, and more patina. I didn't find out if this was a field or a creek find--the finder passed the piece to his son, and then on to the third generation (also now deceased). The widow knew the collection had been found in various places in Perry and Spencer County, Indiana, s.w. corner of the state. Flint is right (our Harrison County Hornstone), type is right (something like 98% of all Turkey Tails are made of Indiana Hornstone, I've read)--and area, every trait matches for what an authentic Turkey Tail should be. Length is right under 2&15/16" by 1&1/4", with a thin profile, only 1/4" max thickness. One side of the blade saw more use (and sharpening) than the opposite blade edge--you can see it's cut closer to the stem by a small degree--the tip, too, shows ancient (Late Archaic, some 2500BP) use and edge sharpening. The stem edges show some grinding to save the sinew used to secure the knife into a handle (wood or more likely antler--a semi-curved antler which would account for more wear on the main cutting edge. Visualize holding a curved antler, how awkward it'd be to use the edge facing up...much like a steel steak knife). Shipping is $8.00, and payment can be by cash, check, or money order, but please note this store does not use paypal-type services--Roy A.