Called the Artist Drive Formation, the rock unit provides evidence for one of the Death Valley area's most violently explosive volcanic periods. The Miocene-aged formation is made up of cemented gravel, playa deposits, and much volcanic debris, perhaps 5,000 feet (1500 m) thick. Chemical weathering and hydrothermal alteration are also responsible for the variety of colors displayed in the Artist Drive Formation and nearby exposures of the Furnace Creek Formation." - Wikipedia
This pan was first created by the drying-up of 30-foot (10 m) deep Recent Lake 2000 to 3000 years ago. Unlike at the Devils Golf Course, significant rainstorms flood Badwater, covering the salt pan with a thin sheet of standing water. Each newly formed lake doesn't last long though, because the 1.9 inch (48 mm) average rainfall is overwhelmed by a 150-inch (3800 mm) annual evaporation rate. This, the nation's greatest evaporation potential, means that even a 12-foot (3.7 m) deep, 30 mile (50 km) long lake would dry up in a single year. While flooded, some of the salt is dissolved, then is redeposited as clean, sparkling crystals when the water evaporates." - Wikipedia
Don't come after me, I didn't take the Badwater sample! I obtained this sample at the Boston NSTA Convention in 1998 (I think). I went to see "The Sand Man," and he gave everyone a huge bag of sand samples. This was one of them.