The desert is located in the Tularosa Basin of New Mexico. Its white sands are not composed of quartz, like most desert sands, but of gypsum and calcium sulfate. Unlike other desert sands, it is cool to the touch, due to the high rate of evaporation of surface moisture and the fact that the sands reflect, rather than absorb, the sun's rays. At 1185 meters above sea level, there are approximately 442 square kilometers of dune fields and is known to be the world's largest surface deposit of gypsum.