Q: I just purchased an extremely light colored travertine slate for my front room, but would like a richer, darker color for the slate. Since it has not yet been sealed, can the slate be "colored" or "stained" before it is installed?

A: Are you referring to travertine or slate? It’s either / or -- no such thing as travertine slate. However, the answer is that, yes, both can be darkened. If it is travertine, it will be darkened some with an enhancing sealer. Slate will have more of a dramatic darkening.

I would not recommend darkening the stone before installation. You may want to darken one sample tile to see if it’s the finish you desire. The rest of the tiles can be color enhanced once installation has been completed. Always make sure your stone surfaces are cleaned thoroughly with stone safe cleaners (no acidic products! stick with products formulated for your stone) before ever applying any type of stone sealer. Not having a clean slate will trap dirt resulting in a poorly sealed stone and produce an unsightly appearance. 

The product you need is called a color enhancer or color enhancing sealer, available at Stone Care Central. They also have the pH neutral stone cleaner that you will require for this type of work.

Fred Hueston, Chief Technical Director, Stone and Tile PROS