Have you ever heard of Doctored Travertine?
Q: In India, I have heard that Travertine stone is doctored by adding a substrate to the base of another hard cheaper stone. How can I know whether it is so without breaking it?
A: Many of the black granites from India are darkened with dyes, but to my knowledge travertine is not doctored. There are however fillers that are used in travertine to fill the voids. It’s possible that they use some other stone ground up with cement to fill these holes. But this should not have any effect on the quality of the stone.
If you dealing with black granite and want to test it for dyes there is a testing kit available at available at Stone Care Central.
Fred Hueston, Chief Technical Director, Stone and Tile PROS