Both marble and granite are extracted from the earth, but they have very different qualities. Marble is completely smooth and cool to the touch, which makes it ideal as a pastry slab and for use in bathrooms and living room surfaces. However, it is made of calcium carbonate, which reacts to food acids such as vinegar and citrus fruits, so it is prone to etching. Granite, on the other hand, is non-reactive and much tougher than marble, so it is the stone of choice for kitchens. It should be noted that because granite is crystalline in nature, it may contain some pits and fissures. These are not defects, but an integral part of the stone itself. This is the reason why granite is always sealed prior to installation.