The above image is of a naturally occurring mineral called gypsum which is found in the Sahara desert in southern Tunisia. It is known by the name of "desert rose" here as the gypsum formations are said to resemble the petals of a rose. It is possible to see desert rose crystals on sale in tourist shops.
"Desert rose is the colloquial name given to rosette formations of the minerals gypsum and barite with poikilotopic sand inclusions. The 'petals' are crystals flattened on the crystallographic axis, fanning open along characteristic gypsum cleavage planes.
The rosette crystal habit tends to occur when the crystals form in arid sandy conditions, such as the evaporation of a shallow salt basin. Gypsum roses usually have better defined, sharper edges than barite roses." http://en.wikipedia.org/wiki/Desert_rose_(crystal)