This is a Fossil Horse Tooth aka Equus sp. This was found in Suwannee River, Florida. This piece measures approx. 52 x 25 mm: thickness is 14 mm: weight is 35 grams. 
 
Fossilized Horse Tooth from a horse that roamed Florida during the last Ice Age over 10,000 years ago. The Horse actually started out in America, the Equus species lived here during the Pleistocene epoch that was 10,000 to 1.8 million years ago.