Gypsum, Desert rose var.

Gypsum, Desert rose var.

Gypsum, CaSO4. 2H2O  Calcium Sulfate dihydrate is an evaporite mineral which is found in arid areas where salt rich lakes have dried up, leaving the flower like constructions  known as desert roses. The reddish colour is the result of sand grains incorporated into the crystals during growth. This specimen is described as coming from Morocco.