The sand at White Sands is white because it is made of gypsum.
According to information from Kenneth Ferguson / NM News Port, the White Sands monument features extensive high dunes composed of broken down gypsum. This gypsum is the material that creates the appearance of a pristine white desert, attracting over half a million visitors annually. The source of this vast amount of gypsum is described as having been at the bottom of a deep lake millions of years ago. Over time, this gypsum was exposed and broken down into the fine white sand that forms the unique dunes visible today.
