This is a large fossil shark tooth from the extinct Mako shark called Isurus hastalis. This prehistoric shark is a member of the White Shark family. Teeth from Isurus hastalis look remarkably similar to the modern Great White Shark less the serrations. Little is known about this species and it is classified in the genus Isurus (Mako) due to its characteristic smooth edges. Some consider this shark the "Grandfather of the Great White".
This tooth is a large tooth from the upper jaw, and is complete. The enamel has a natural luster and features a nice lighter color than usual.