Ceramic Heat Lamps create heat, but not light. It seems to last longer than the light bulbs, which is a good option if you want to keep a good temperature through the night. On the other side, Mercury Vapor Bulbs is an all-in-one product, including light, heat and even UVB for raising a healthy tortoise. It comes in really high wattages, so make sure that your lamp will accommodate a high wattage bulb to prevent fires.
To sum up, you should use a Mercury Vapor Bulb since it provides both heat and light.