We purchased an $800 vanity with "marble" black top and I put a water glass on it while installing and it made a white stain on it. I complained to Rona and they said it is made in china and not "real" marble and getting it wet took the dye out. "Don't get it wet" she said.
A vanity??? Don't get it wet? good grief. They didn't offer to pay for any dye or product that I might try but suggested to avoid further stains to buy some varathane to protect my "marble" top.