Yes this is a real Buckeye nut. I made a pilgrimage down to Mohican country to the historical landmark, Malabar Farm in central Ohio.
In case you're wondering about that, the farm was home to the late prolific author, Louis Bromfield who authored such works as Pleasant Valley, It Takes All Kinds, Animals and Other People and Eary Autumn (won a Pulitzer Prize!) among others. He was a prolific writer in the early part of the 20th century and some of his books have ben made into movies in Hollywood. Further he was friends with F. Scott Fitzgerald, Ms. Gertrude Stein and Ernest Hemingway all of whom spent time in Bromfield's home.
In fact, there are haunted tours offered of Bromfield's home and areas on Malabar Farm during select months of the year. I plan on taking one of these myself soon.
home to pick Buckeyes from the trees before the squirrels got to them.
These Buckeyes are from the Mohican area of the state and were carried long ago by our ancestors as charms to ward off rheumatism and arthritis.
Other folklore indicated that you wrap a new one dollar bill around the nut and carried it in your left pocket (heart side) for good luck & prosperity purposes.
I recommend to my students to anoint the Buckeye nut with some High John the Conqueror oil prior to wrapping the one dollar bill around it.
Some folks take the charm then put it into a Gris-Gris bag then carry it. That's a nice way to keep the charm from getting dirt & lint from your pocket on it.
Size of the nut does not diminish its effectiveness as Buckeye nuts come in many size range. These I have kept charging under a Radionic Pyramid on my altar since I picked them and they are ready for you to use.