Squire Boone – Gypsum is a type of sedimentary rock called an evaporite. It is formed at the bottom of shallow baodies of salt water containing calcium and sulfur. As the saltwater evaporates, dissolved calcium and sulfur in the water become concentrated and precipitate as the mineral gypsum.

Gypsum crystals occur in the rose-shaped aggregates, often incorporating grains of sand. These gypsum “desert roses” grow by replacing carbonate sediment in the siol overlaying gypsum deposits.