Gypsum

The dunes of White Sands National Monument were gypsum sand.  Years ago gypsum was deposited at the bottom of a shallow sea.  Normally gypsum would have disappeared over the years since it is soluble in water. However water doesn’t drain to the sea in this area so the gypsum stayed and eventually broke up into sand.

Near Roswell we stopped at Bottomless Lakes State Park.  The ‘bottomless’ lakes are actually up to 90 feet deep sinkholes.  The bluffs nearby are gypsum while the water has gypsum dissolved in it.  This leaves crystals on the shore.  I’ve seen samples of gypsum before in rock collections, but this is the first time I’ve seen it “wild”.  Pretty cool!