Hearth is the inner floor of the fire place where the fire is built. It is made of non-combustible material. They are in continuation with the design of the surrounds and the floor. They extend the mood of the fireplace to the last detail.
It can be of granite, marble, lime stone etc. since they all are fire proof. It is preferred to be of the same material as the surround to maintain the continuity. Today it is also used to refer to all the devices and equipment used in connection with the fireplace and the stove industry.