1. Got sand? You probably do, in your kitchen pantry. Sand is defined as any material made up of grains within a specific size range. Sugar and salt typically qualify.
2. Much less common, however, is gypsum sand, which gives White Sands National Monument in New Mexico its name. The site’s unusually high concentration of the rare variety started out as a shallow seabed about 280 million years ago.
3. The material most commonly thought of as sand is silica, made of quartz crystals that have broken down about as far as they will naturally, to about a millimeter in diameter.
