Hi,
I just looked and tested an antique grey marble shelf that an antique dealer has.  Basically he wanted it polished up and asked someone trusty with auto polishing equipment.  I think he took some maguires and polished the whole thing up at a high speed.  In the process he creates some serious white marks that the antiques dealer has now asked us to try to remove. I did some tests this morning.  These are not etch marks.  I think they are either stun marks or the heat and chemicals metamorphosized some of the stone.  I tested a few small areas by honing back to 200 grit, applying some color enhancing sealer, taking back up to 800 and polishing.  I got some color back and a better shine, but couldn't get rid of the whiteness entirely. I also tested an area with just polish and, although it made it very glossy, it didn't take any of the whiteness away. 

One approach might be to hone it all back to 100 and see if it gets some or all off (I suspect that if these are stun marks, they may be pretty deep, or at least some of it may be pretty deep).  Also, was thinking that I might be able to rub in a colored dye or perhaps a powder such as the kind that comes in the touchstone epoxy kit to get some of the grey back.  Could also try a dark granite polish maybe.

But basically I have never really seen a thing like this.  Any advice would be very much appreciated.  I pasted below a before and after and an overview of the entire shelf.  You an see that I was able to eradicate the strong white line in the center somewhat (where I tested.  I  tested that one small area only.  Thanks,
Baird

Inline image 1  Inline image 2  Inline image 3

--
PLEASE NOTE OUR NEW ADDRESS AND PHONE NUMBERS.  THE OLD NUMBERS WILL WORK FOR SOME PERIOD OF TIME.
________________________________________
From the desk of
Baird Standish
Managing Partner
Facility Specialists, LLC
15 West Highland Ave.
Philadelphia, PA 191118
Phone: 267-331-5369
Fax: 267-331-5771