Photo of the Day (POTD): December 4, 2019

Gypsum crystals from drying mudflats are blown into dunes patterned with sinuous ripples along the eastern margin of the Great Salt Lake Desert. Gypsum—an evaporite mineral that is soluble in water—is an uncommon constituent of sand.

Knolls Dunes, Tooele County, Utah. Photo by Andy Cvar.