Originally Posted by Keith Outten
Steve,
Im not sure about the white material but the black tile sounds like marble. Marble is a natural stone that is available everywhere in the USA but for engraving purposes you want to use a marble that does not contain any veining. A solid black marble withour veining is imported from China and available from a dealer in Georgia, I think I already sent you the link to their web site.
There is also a black granite that is supposed to engrave well but I haven't found a source yet. If you can't find a source for a white material try Corian, use a mask and paint as required.