Desert rose is the colloquial name given to rose-like formations of crystal clusters found in arid environments around the world. The most common mineral compounds that create the distinctive desert rose shape are barite and selenite. While both minerals can develop the characteristic sandrosa or desert rose shape and appearance, there are some key differences between barite and selenite desert roses.
Barite Desert Roses
Barite desert roses are much more common than selenite roses. Barite is a barium sulfate mineral that crystallizes in an orthorhombic system and forms rosette shaped clusters. The mineral composition gives barite roses a relatively high density at 4.5 on the Mohs scale. Barite roses grow as interlocking blades of barite crystals that radiate outward from a common center. This creates the signature desert rose shape that resembles an open rose flower.
Barite crystals come in a range of colors from red, brown, yellow, and white depending on mineral impurities. Iron oxide impurities give some barite roses a distinctive red or burnt orange hue. Barite is insoluble in water and has a vitreous to pearly luster. The desert roses can form as small isolated clusters or aggregate into large formations weighing several pounds. They are found in sedimentary rock regions with barium rich waters. Well-known locations to find barite roses include the Mojave Desert, Oklahoma, and Tunisia.
Selenite Desert Roses
In comparison to barite, selenite desert roses are quite rare. Selenite is a crystalline variety of the mineral gypsum. Chemically it is calcium sulfate dihydrate. Selenite crystals have a white, pearly luster and perfect cleavage. The Mohs hardness is only 1.5-2, making it very soft and fragile. Selenite roses grow as transparent, twinned crystal blades in a radial pattern from a central originating point.
Unlike barite roses, selenite roses will slowly dissolve if left sitting in open air or water. Prolonged exposure to moisture causes the desert roses to lose their crisp, well-defined shape. For this reason, selenite roses tend to be small and delicate looking. The largest specimens may be only 2-3 inches across. Selenite roses are found in arid regions with evaporite deposits like Mexico, Morocco, and the Southwestern United States. The best specimens come from Naica and Chihuahua, Mexico where hexagonal crystals with diamond-like clarity are found.
While both can produce the diagnostic desert rose shape, barite roses are the much more common type found. Barite's hardness and insolubility allow large plump roses to develop sturdy crystal structures. The soft, water-soluble nature of selenite make intact roses a rare find. So while both can be classically desert roses, the minerals have distinct properties that set them apart.
