Slippery Rock Gazette

Frederick M. Hueston, PhD

It was a typical Wednesday evening. I was just getting ready for my weekly radio show. I’ve been broadcasting “The Stone and Tile Show” (blog
talkradio.com/drfred) for a while now and have gotten some interesting calls. 

This week would turn out to be unusual. I got on the air and started interviewing my guest about some new anti-etch products when someone called in to ask a question. He started by asking questions about the anti-etch products, and then he sprung the following question on me. He told me that he represented a large condo complex and that all the countertops were Black Absolute, and all of them were etching. My first thought was that he really didn’t know what etching was, but after several minutes of explaining the problem, I asked him to send me a photo. I also asked him to hold while I continued my interview on air.  As I was discussing several interesting points, the photo came through on my phone. I then told the interviewer to hold a second while I described the photo to him and my audience. Sure enough, it looked like Black Absolute granite and did look like it was etched. My first thought was that it was dyed granite. I put him back on the air and told him I would call him later to discuss. I continued my interview and wrapped up the show. 

I immediately called the gentleman with the etched Black Absolute and got some more information. Based on what he told me, I really couldn’t put my finger on why this granite would etch. I told him I would be available to fly out there to take a look. Oh yeah, the project was in the Cayman Islands. Hey, it’s a tough job but I knew I’d have to go. He agreed, and I booked a flight for the following week.

I packed my swimming trunks, and I was off to the islands. No, I did not plan to do the inspection in my swimming trunks, but after all, I was in the Caymans! I just knew I would have to go to the beach while I was there (LOL). I know, poor me. 

Anyway, I arrived at the airport and was greeted by a lovely island lady holding a sign with my name on it. I introduced myself and we were off to the building. I asked to stop at a hardware store first to pick up some acid for my testing. The TSA folks don’t like you carrying that on a plane for some reason.

We stopped at the store and we were back on the road to the suspected building. The drive was beautiful as we cruised along the ocean. All I could think of was getting into that blue water when I finished my inspection. 

We arrived at the building, a tall skyscraper in downtown Georgetown. Georgetown is where all those “offshore” banks are located that you hear about all the time, where people stash all their millions. I wouldn’t know (LOL). 

We entered the building and there were at least eight people waiting for me. A tall gentleman who had a Scottish accent greeted me. He told me he was the head architect and was very concerned with this issue. They led me to one of the units and into the kitchen. As soon as I looked at the countertop I could not believe my eyes. The countertop certainly was etched. I took out the small bottle of acid and placed a drop on the countertop and it started fizzing in several places. Without a doubt there was calcium in this stone. I recalled a time I had a similar problem and had the stone tested. The problem was this granite had some calcium binders in it. For those of you who don’t know, calcium is the main mineral in marble and will react to acids. Some granite can contain calcium depending on its geological age, section of the quarry, as well as where in the rock cycle it is. This was the case here, as well. I suggested that they either have them restored, then use an anti-etch product, or just replace them. I’m still waiting to see what they decided.

Yes, Virginia, granite can etch, under the right circumstances and composition. However, it is unusual for Absolute Black granite.

For those of you interested in anti-etch products, I’ve interviewed several experts on this very topic. Listen to my Stone and Tile Show – blogtalkradio.com/drfred.

Another case solved – now off to the beach!

The Stone Detective is a fictional character created by Dr. Frederick M. Hueston, PhD, written to entertain and educate. Dr. Fred has written over 33 books on stone and tile installations, fabrication and restoration and also serves as an expert for many legal cases across the world. Send your email comments to him at fhueston@stone forensics.com.