A potential customer would like to have this stone cleaned and color sealed. She and her retail salesman claim it to be a travertine. It is installed on an outside covered patio with a sanded grout. I'm suspect as to the stone id since my acid test (pH2) on the stone showed it not to be reactive to acid. It did not fizz or do anything like when a acid comes in contact with a marble. I attempted to color enhance a couple of tiles with minor noticeable improvement. It just did not absorb the enhancer at all. It shows me that the stone is not very porous had has very little permeability. Are there such travertines? Looks to me like some fancy man made stone, but kind of hard to argue that point with her or her salesman. When she wets the stone with water the colors just burst out. She would like to see a similar kind of finish with color enhancing. Any ideas?