I recently had a stone “granite” installed known as Shanxi Black, which is actually a type of basalt. This stone is very dense and doesn’t seem to accept any type of sealer I put on it.
The other day I had set a plastic cup with water in it on the countertop near the sink. I left the cup overnight, and in the morning, I noticed that the condensation ring had left a white ring in the stone and it looks like it actually etched the surface of the stone.
I have tried acetone, sealer, color enhancer, etc to remove the white ring. I had the installer come back out and try to remove the ring and he was unable to.
Do you have any ideas how water can damage the color and surface of such a “bullet proof” material?
I know the Shanxi Black very well. In my opinion it is the best black stone in the world when it is selected without the metal spots. If the finish surface is polished, then I am baffled by water leaving a mark like this. That just does not happen. If the surface is honed, then yes, water can leave a mark and could take a long time to evaporate. My other guess is that the stone is not actually Shanxi Black. I believe that Shanxi black is an Anorthosite, not a basalt. I am aware of other black stone from China that are very porous and could leave a watermark as you mentioned.
Shanxi Black is relatively expensive and the other softer blacks are cheap. Perhaps a local expert should help you further.