That’s a rock. How was it dated?
If it has intact DNA or proteins or intact egg membranes it cannot be that old. Those molecules don’t last that long in lab studies.
The only reason that some think it lasts that long is because they are finding proteins or collagen or rbc’s in dinosaur bones... there’s a whole industry trying to find a natural mechanism that preserves such biochemicals for 65 million years....a much less popular explanation is that the specimens are much younger.
If this egg contains ancient dna, or proteins it may be a relatively young specimen ..
IMHO