Described is a high intensity discharge lamp including a lamp bulb envelope, first and second electrodes, a seal and a fill situated within the lamp bulb envelope. The lamp bulb envelope is composed of single crystal sapphire tubing. The lamp bulb envelope includes end portions and a central portion, the central portion having a greater diameter than the end portions. The end portions may be a cylindrical tube shape and the central portion is a smooth three-dimensional shape. The first and second electrodes extend through opposite ends of the lamp bulb envelope so that at least a portion of each of the electrodes is situated within the lamp bulb envelope. The seal seals each of the first and second electrodes to an inside wall of the corresponding end of the lamp bulb envelope. A voltage is applied to the first and second electrodes to generate an arc plasma therebetween.