Banded Shark egg looks like dry mango seed.Be careful when u buy it from the LFS.If happen that there is air bubbles trap inside the egg when u take it out of the water, u need to submerge the egg to remove the bubbles.If not,the baby will die inside.
It take abt 2-3mths to hatch and depend on when the egg is imported.When the egg is going to hatch, u can see that the surface of the egg is getting clearer.
I think that it would be a good idea if you check out on any fishes before you buy lor.