GREAT SAND ROSE, also DESERT ROSE, BARYTROSE from the Sahel; crystalline, water-soluble formation mostly of sand grains embedded in a crystal of gypsum or baryte. Sand roses are formed in hot and dry desert areas by rapidly evaporating surface moisture, which transports groundwater upward by capillary forces. In the process, the salts dissolved in the water crystallize and, together with the sand, form the characteristic leaf-like structures. Weight approx. 26.8 kg, H. 18 x L. 52 x W. 40 cm. (Self-collection or shipping by forwarding agency; parcel shipping not possible because of the sensitivity of the object).