Hi Trisha,

Since most kitchen backsplashes are about 18" from countertop to upper cabinets, I'm a fan of 3x6" and 4x4" travertine tiles. 6x6" feels a bit big unless you have a taller backsplash. If you can find them, longer sizes such as 3x12" also look nice.

As for color, a lighter color (cream, ivory, or chiaro) like what we have in the picture will contrast nicely with the Black Galaxy, but you could also use a darker color such as noce (pronounced no-chay) or walnut since you have lighter cabinets.

It really depends on how much light you have in the kitchen: a lot of natural light or under cabinet lighting? You can have a darker backsplash. Not a lot of light? I recommend a lighter-colored backsplash.

The nice thing about travertine is that it's a common enough stone that you can find it at nearly any tile store. Just check the back of the tile before you buy. If it's severely pitted, it's a lower quality stone that will be very crumbly. If it's pretty dense with only a few little pits and holes, it will be easier to install and a better looking product.

Hope that helps!