Out of a S.W. Indiana collection, but not marked if it was part of the famous Spencer County, Indiana, "Crib Mound Cache" (somewhere between 10,000 and 14,000 blades found together, depending on which source you read)--the blade shape, the mineral adhesions on one face, the piece was very likely part of that enormous Cache, This one ended up in a Gibson County, Indiana, collection, but in fairness there are likely Crib Mound blades in all fifty states by now, plus foreign countries. The blades themselves are assumed to be Adena Culture. This one measures a full 5&3/16" by 4&3/4", max thickness of 13/16"--considerably larger than most of the Cache Blades (you can find pictures either online of it Art Gerber's book on Crib Site). The piece is an extremely good grade of Harrison county-type Hornstone, it shows a bit of a glossy white cortex near the tip--the flat-edged inclusion is almost a white chalcedony-grade material.. The blade is absolutely guaranteed authentic, period. Shipping is $10 due to the weight. Checks are welcomed, money orders as well, but I do not use paypal--Roy A.