What's this book?

[SmokeAndBone]

In this book, a man is creating a mosaic and he says that it has to have darker shades in order to make the light ones show up.
I think the whole novel has a religious theme...

Not much to go on, sorry.

Is this a recent book? If so, possibly The Gospel According to Lazarus by Richard Zimlet

That should be Zimler

Was it set in a Greek coastal town? A woman moved there from UK? It sounds familiar