Absolute Black - getting grey rings?! Found solution!
Have been reading here and other forums that people are having issues (grey marks, grey rings, etc) with their Absolute Black granite. Noticed this when I was trying to solve problems with my tops. I wanted to pass along my experiences and safe solution to remove them.
FIRST: Impregnator Sealers are evil and if your tops are sealed you will go crazy when grey rings start to appear on your tops.
I have two full slabs of Premium Absolute Black (polished) installed in my kitchen along with a double thick Imperial Danby Island. Few months ago left a plastic pitcher of Lipton's Ice Tea that must have dripped on the side of the pitcher. Guess what - left three nasty grey rings on the top. Our tops were sealed with Impregnator 511.
Very concerned that the tops were either doctored or treated I did several tests on a spare piece I had in my basement and I duplicated the etch. No black on the cloth when the stone was saturated in acetone and the edges were field polished to the same black color so the stone isn't doctored or enhanced.
In my research I've come to the conclusion based on what other fabricators have determined that AB Black shouldn't be sealed and you will have more problems with a sealer than without. The reason has to do with the density of the AB Black. Its just too dense for the sealer to get into the stone and it just sits on top as a thin layer. Sealers are not impervious to acids and as a result the top layer just etches and the marks you see are the change in color to the sealer not the stone. Assuming that your stone is truly AB Black - see my tests below. The sealer company, my fabricator, distributor and everyone online including fabricators had no clue on how to remove the sealer effectively and safely. Tried everything including acetone, toulene, xylene, etc. Finally stripped the stone with methylene chloride which is strong stripper. Very caustic and can ruin your cabinets or backsplash. In my case its marble and it will etch that. The sealer was removed and the etch disappeared with a little elbow grease. Don't think it changed the polish but I wasn't able to re-etch the stone again with anything including pure lemon which was left on the stone for more than 3 days. This step was key. Since the stone passes the lemon juice test I can assume it doesn't contain enough calcites - which some AB Black have that can cause them to etch as well. If your stone has concentrations of calcite which is calcium it will etch like marble and it too will drive you crazy keeping the stone looking like new. This is the second worse case next to having a doctored stone because you can't fix it easily except to have it re-polished BUT it will continue to etch when exposed to anything acidic.
So if you have AB Black and are getting rings what do you do? Yes you can strip it but its very dangerous to the surrounding area and it can dull the stone a bit which means an expensive re-polish which is VERY difficult to do on AB Black without swirls.
What I found is the perfect product that is 100% safe to you and the stone. It will remove the sealer completely and will also remove the rings or grey marks from acidic foods. Chemically, a polymerized silicone is EXTREMELY difficult to remove and even with nasty solvents except for caustic chemical stripper.
The product is called DICONE NB9 and is specifically designed to remove polymerized silicone sealers - thats what is in nearly all impregnators. Its produced by a company called Proseco. I have no affiliation with them but I wanted to share my experience and hopefully eliminate some sleepless nights and pain when looking at a perfectly black top with grey stains that you can't get out. You have to purchase it at a commercial distributor - see their website. Its designed for large scale commercial applications - like cleaning high rise building, monuments but it works on any stone.
Its not cheap - about 60-80 per gallon but it works in 30 minutes and is very effective. You will see and feel the silicone being leached out of or from the top of the stone. The marks will also go away in the same amount of time. Will not alter the polish or change the color of the stone in any way. You do have to be careful around any areas of your counter that were caulked with silicone or acrylic caulk (generally has some silicone) and the Dicone will dissolve the caulk as well or at least make it gummy.
I haven't tried it but for those who also have problems with grey rings on honed AB Black I believe it will remove them as well.
Lastly, I know this was long - don't listen to your fabricator or stone supplier. I would guess based on my experiences with nearly everyone in town - ST Louis and other fabricators nationally that your tops are doctored and nothing can be done or they contain calcite. Also don't listen to them when they say all granite tops should be sealed and they have never had a problem with a sealed AB Black. If they are sealed and are not doctored THEY WILL ETCH - the stone won't etch but the sealer will showing a grey/light mark IN THE SEALER. AB Black is extremely dense and if the stone is good it shouldn't stain with oil, etc so no sealer is necessary.
Hopefully someone that has this problem or is looking to do AB Black in their house can use the very extensive research that I have compiled over the last few months to eliminate the problems I've had with my tops.