The white walls shouldn't be part of the equation. They're only white because it's one of the builder's limited color options. Eventually you will paint the walls something you like.
Pick the granite color you love the most. That fireplace will be there much longer than your kitchen. Kitchens get remodeled ever couple decades. Fireplaces don't get a face lift for a half a century to a century.
Look at all of these fireplace pictures in google images. See what you like best. Darker wood? Lighter wood? Painted wood? Darker tile? Lighter tile? Tile that matches the wood?
fireplace - Google Search <<<<<THAT will help you figure out your fireplace style preference.