This is a partial fossil tooth from the large armored nodosaurid dinosaur Edmontonia rugosidens found in the Two Medicine Formation, U.S.A.. It is split in half so from one side, it looks complete but the back side is missing. The interesting feature though, is that you can see the inside of the tooth and its internal structure because of this! The tooth has a richly colored hue and a naturally lustrous finish. An important specimen if collecting the lineage of armored dinosaurs as Edmontonia was one of the largest and last of the nodosaurids. Not usually offered for sale as much as many other dinosaur teeth and fossils.
Edmontonia rugosidens was about 20 feet in length and weighed as much as 4 tons. Edmontonia was a nodosaurid so it lacked a tail club. This armored dinosaur was very heavy in build with a low, long and wide skull as well as a frightening array of long, robust spikes projecting from its shoulders and running down both sides, in diminishing proportions, to its tail.