Both are natural stones that are quarried from the earth however granite and marble (and marbles relatives limestone, onyx and travertine) are quite different from one another. Granite is formed deep within the earths mantle at extremely high temperatures making it a very hard resilient stone made of crystallized minerals. The marble family (marble, limestone, onyx and travertine) starts out as sediment (animal skeletons, plant matter & silt) at the bottom of a body of water. Over millions of years this sediment solidifies into stone. Because the main component of these stones is calcium, they can be affected by acids such as vinegar and citrus juice.