Lake Lucero is a playa located within that section of the Tularosa Basin that is contained within the White Sands National Monument in the U.S. state of New Mexico. The playa is noted for the unusually high quantity of water-deposited and wind-deposited gypsum dissolved in its intermittent waters. Annual evaporation cycles have caused much of the gypsum to precipitate into crystals of impure, brownish selenite that line the alkaline mudflats of the lakeshore. The further process of gypsum erosion abrades the fragile selenite, and other precipitated gypsum, into the pure-white sands covering most of the national monument.