A desert rose, sand rose,

Sahara The Sahara (, ) is a desert spanning across North Africa. With an area of , it is the largest hot desert in the world and the list of deserts by area, third-largest desert overall, smaller only than the deserts of Antarctica and the northern Ar ...

rose, rose rock, selenite rose, gypsum rose, or baryte rose is an intricate

rose A rose is either a woody perennial plant, perennial flowering plant of the genus ''Rosa'' (), in the family Rosaceae (), or the flower it bears. There are over three hundred Rose species, species and Garden roses, tens of thousands of cultivar ...

-like formation of

crystal cluster A crystal cluster is a group of crystals which are formed in an open space environment and exhibit euhedral crystal form determined by their internal crystal structure In crystallography, crystal structure is a description of ordered arrangeme ...

s of

gypsum Gypsum is a soft sulfate mineral composed of calcium sulfate Hydrate, 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, drywall and blackboard or sidewalk ...

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 aggregate of crystals. The habit of a crystal is dependent on its crystallographic form and growth conditions, which generally creates irregularities d ...

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 Pea (''pisum'' in Latin) is a pulse or fodder crop, but the word often refers to the seed or sometimes the pod of this flowering plant species. Peas are eaten as a vegetable. Carl Linnaeus gave the species the scientific name ''Pisum sativum' ...

-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 An iron oxide is a chemical compound composed of iron and oxygen. Several iron oxides are recognized. Often they are nonstoichiometric, non-stoichiometric. Ferric oxyhydroxides are a related class of compounds, perhaps the best known of which is ...

are present, the rosettes take on a rusty tone.

Locations

Sahara

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

Chott el Djerid Chott el Djerid ( ') 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". Geography The bottom ...

in southwest Tunisia, as well as the neighboring regions in Algeria and

Ghadames Ghadames or Ghadamis ( Ghadamsi: ⵄⴰⴷⴻⵎⴻⵙ / ''Ɛadēməs'' �adeːməs , ) is an oasis town in the Nalut District of the Tripolitania region in northwestern Libya. Ghadamès, known as 'the pearl of the desert', stands in an oa ...

, Libya. Local inhabitants extract them and sell them as souvenirs to tourists, creating a sustainable income for the 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 and are hence less brilliant in light. Sand roses are also found in the vicinity of Abqaiq, Saudi Arabia.

Oklahoma

Rose rock in

Oklahoma Oklahoma ( ; Choctaw language, Choctaw: , ) is a landlocked U.S. state, state in the South Central United States, South Central region of the United States. It borders Texas to the south and west, Kansas to the north, Missouri to the northea ...

was formed during the

Permian The Permian ( ) is a geologic period and System (stratigraphy), 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 251.902 Mya. It is the s ...

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 rock#Sedimentary clastic rocks, clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains, Cementation (geology), cemented together by another mineral. Sand ...

, locally called Garber Sandstone, containing deposits of rose rock. The rose rock was selected as the official rock of Oklahoma in 1968.

Size

Typically, desert roses measure from in diameter. The largest recorded by the

Oklahoma Geological Survey The Oklahoma Geological Survey is a state agency chartered in the Constitution of Oklahoma responsible for collecting and disseminating information about Oklahoma's natural resources, geological formations, and earthquakes. Shortly after Oklahoma b ...

was across and high, weighing . Clusters of rose rocks up to tall and weighing more than have been found.

References

External links

Timberlake Rose Rock Museum
in

Noble, Oklahoma Noble is a city in Cleveland County, Oklahoma, United States, and is part of the Oklahoma City Metropolitan Area. The population was 6,985 at the 2020 census, a 7.8% increase from 2010. Noble is Cleveland County's third-largest city behind N ...