A desert rose is an intricate

rose A rose is either a woody perennial flowering plant of the genus ''Rosa'' (), in the family Rosaceae (), or the flower it bears. There are over three hundred species and tens of thousands of cultivars. They form a group of plants that can b ...

-like

formation Formation may refer to: Linguistics * Back-formation, the process of creating a new lexeme by removing or affixes * Word formation, the creation of a new word by adding affixes Mathematics and science * Cave formation or speleothem, a secondary ...

of crystal clusters of

gypsum Gypsum is a soft sulfate mineral composed of calcium sulfate dihydrate, with the chemical formula . It is widely mined and is used as a fertilizer and as the main constituent in many forms of plaster, blackboard or sidewalk chalk, and dr ...

baryte Baryte, barite or barytes ( or ) is a mineral consisting of barium sulfate ( Ba S O4). Baryte is generally white or colorless, and is the main source of the element barium. The ''baryte group'' consists of baryte, celestine (strontium sulfate), ...

, which include abundant sand grains. The "petals" are crystals flattened on the ''c'' axis, fanning open in radiating clusters. The rosette

crystal habit In mineralogy, crystal habit is the characteristic external shape of an individual crystal or crystal group. The habit of a crystal is dependent on its crystallographic form and growth conditions, which generally creates irregularities due to l ...

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 An evaporite () is a water- soluble sedimentary mineral deposit that results from concentration and crystallization by evaporation from an aqueous solution. There are two types of evaporite deposits: marine, which can also be described as oce ...

minerals may also form rosette clusters. They can appear either as a single rose-like bloom or as clusters of blooms, typically ranging from pea-sized to in diameter. The ambient sand that is incorporated into the crystal structure, or otherwise encrusts the crystals, varies with the local environment. If iron oxides are present, the rosettes take on a rusty tone. The desert rose may also be known by the names: sand rose,

Sahara , photo = Sahara real color.jpg , photo_caption = The Sahara taken by Apollo 17 astronauts, 1972 , map = , map_image = , location = , country = , country1 = , ...

rose, rose rock, selenite rose, gypsum rose and baryte (barite) rose.

Locations

Sahara

Sand roses are found in large numbers in surroundings of the salt lake of

Chott el Djerid Chott el Djerid ( ar, شط الجريد ') also spelled ''Sciott Gerid'' and ''Shott el Jerid'', is a chott, a large endorheic salt lake in southern Tunisia. The name can be translated from the Arabic into English as "Lagoon of the Land of Palms" ...

in South-West Tunisia, as well as the neighboring regions in Algeria and

Ghadames Ghadames or Ghadamis ( Berber: ''ʕadémis''; ar, غدامس, Libyan vernacular: ''ɣdāməs'', Latin: ''Cidamus, Cydamus'', it, Gadames) is an oasis Berber town in the Nalut District of the Tripolitania region in northwestern Libya. The ...

, Libya. Local inhabitants extract them and sell them as souvenirs to tourists, creating a sustainable income to local population. Other sandroses are found elsewhere in the Sahara, but those extracted in the surroundings of the Salt Lake are particularly beautiful because of the high percentage of salt in their composition making them more crystalline and luminous. Others that contain more sand have a rusty tone, hence less brilliant in day or artificial light. Sand roses are also found in the vicinity of Abqaiq, Saudi Arabia.

Oklahoma

Rose rock in Oklahoma was formed during the

Permian The Permian ( ) is a geologic period and stratigraphic system which spans 47 million years from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.9 Mya. It is the last period of the Pale ...

Period, 250 million years ago, when western and central Oklahoma was covered by a shallow sea. As the sea retreated, baryte precipitated out of the water and crystallized around grains of quartz sand. This left behind large formation of reddish

sandstone Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates ...

, locally called

Garber Sandstone The Garber Sandstone is a geologic formation from the Permian Period in Oklahoma. It serves as an important aquifer, the Garber-Wellington Aquifer, in Logan, Oklahoma, and Cleveland counties of central Oklahoma. The upper portion of the Garb ...

, containing deposits of rose rock. The rose rock was selected as the official rock of the US state of Oklahoma in 1968.

Size

Typically, desert roses measure from in diameter. The largest recorded by the Oklahoma Geological Survey was across and high, weighing . Clusters of rose rocks up to tall and weighing more than have been found.

References

External links