Hey Stephen,

A good percentage of black ab that we see those ghost rings on have been sealed by the fabricator/installer.

The sealer residue is etching-MB-12 or any marble polishing compound usually does the trick.

The bad news is if it is dyed/doctored. We just did one that was etching-they had etches everywhere. Even the sample etched-which we took back to the shop and clean off all the dye on the surface. I lost some of its depth of color but no longer had any thing on the surface, didnt etch and still had a factory polish. We did his whole kitchen with MB-12. They stopped etching.

Do some testing and make sure what you have-each case can be quite different. We had another one with a bathroom vanity bought from a big box. That wasn't black absolute and when we were done with it was a really ugly gray stone. The dye was coming off like crazy using just marble powder polishes.