Granite Sealer Mystery Stains

by Susan
(New York)

QUESTION:

We just had a new Juparana Vyara granite countertop installed. Since installation, there are green spots showing through, traveling the veins where the top/pits were filled. The infiltration resembles the corrosion of a copper penny. At first, a repairman said it was normal and the color of the stone was coming through. I didn't fully believe him, it isn't a natural stone color.

I finally had the owner come out and he is perplexed. He said to give it a week or two to see if it disappears and then call him. Also, if I take a damp sponge and rub hard on the surface, you can see some green come through and then fade. Have you ever heard of a contaminate with the rock like this? What is our course of action? I feel that I will need to replace the entire top. As a side note, one piece that they did not touch/repair, has no sign of this infiltration.

ANSWER:

Susan, I have a couple ideas, but honestly, I'm not quite sure what is happening here. It sounds to me like a reaction of some sort probably between the granite sealer and the repair compound used to fill the pits along the veins.

I do not think it is "normal" and it is not the "stone's color coming through." The stone has been essentially the same color for a few million years now. It won't change unless there is some reaction between it and substances used on it or between substances on the stone.

Another possibility is that the stone had been "resined." This is a common and perfectly acceptable practice that helps fill pits and protect the stone for transport, etc. (Not the same as doctoring the color like what is done to some black granites)

Resins will often seal a stone so it no longer absorbs anything.... which is good, of course....

But that means that any sealer applied would not be absorbed either. Even if the sealer was properly applied and excess was wiped off prior to drying, a residue may still be left causing a reaction with the resin.

You say that you can rub hard with a wet sponge and the green comes through... do you mean anywhere on the countertop or just where the veins are?

If it occurs all over, then it has something to do with the sealer and/or resin. If only in spots where pits were filled, then the reaction is most likely due to the compound used to fill them (with the sealer or something else applied to the granite).

Try this on the section of granite not treated:

Spill a puddle of water on it and let it sit for 5 to 10 minutes. Wipe away the water and observe the area. If it is darker, then your stone can take a sealer. If the stone is not darker, that indicates it did not absorb the water, does NOT need to be sealed and that a resin + sealer reaction may be the issue on the treated sections.

Whatever is happening, it seems it is the responsibility of the installers especially since a section of the same granite, which they did not touch, is not displaying the problem. I'd certainly look to them to make it right even if it means tearing it out and re-installing a brand new slab.

Strange issue. Frustrating I'm sure.

Hope this helps,
Ryan