What is the difference between metal halide and mercury vapor lamps?

The metal halide lamp is very similar in construction to the mercury vapor lamp. The major difference is that the metal halide lamp contains various metal halide additives in addition to mercury vapor. Metal halide lamps are commonly used in stadiums, warehouses and any industrial setting where distinguishing colors is important. Low wattage lamps are available and have become popular in department stores, grocery stores, and many other applications where light quality is important.