Desert rose is the colloquial name given to rose -like formations of crystal clusters of gypsum or baryte which include abundant sand grains. The 'petals' are crystals flattened on the c crystallographic axis , fanning open in radiating flattened crystal clusters. The rosette crystal habit tends to occur when the crystals form in arid sandy conditions, such as the evaporation of a shallow salt basin. The crystals form a circular array of flat plates, giving the rock a shape similar to a rose blossom. Gypsum roses usually have better defined, sharper edges than baryte roses. Celestine and other bladed evaporite minerals may also form rosette clusters. They can appear either as a single rose-like bloom or as clusters of blooms, with most sizes ranging from pea sized to 4 inches (10 cm) in diameter. The ambient sand that is incorporated into the crystal structure, or otherwise encrusts the crystals, varies with the local environment