Is this "black and white crystal" the black and white crystal you are talking about or lying on the surface of the crystal? If these black substances are inclusions, which seem to be wrapped in some dirt, and this is a kind of illusion crystal, such as red ghosts and green ghosts, and the black-and-white crystal you mentioned, if the black part is not inlaid but the inherent color, then this crystal is not natural and should be chemically treated. You can go to the "Crystal Love Mall" and compare the ghost crystals on it to see what's the difference with yours. I hope it helps you.