This is a very rare crystallized dinosaur egg. Its eggshell is still well preserved and the crystals fill the inside of the egg. This is a relatively rare egg fossil besides embryonic eggs. Dinosaur Hadrosaurus egg fossil. They date from the Cretaceous, 72.1-83.6 million years ago. They still have shell covering around surface. Large round eggs are characteristic of hadrosaurs and size of each is about 11*10 cm. Two of them still have eggshells.