Thénardite is an anhydrous

sodium sulfate Sodium sulfate (also known as sodium sulphate or sulfate of soda) is the inorganic compound with formula Na2SO4 as well as several related hydrates. All forms are white solids that are highly soluble in water. With an annual production of 6 mill ...

mineral, Na₂SO₄ which occurs in arid

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 ...

environments, specifically

lake A lake is an area filled with water, localized in a basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, although, like the much lar ...

s and

playas Playa (plural playas) may refer to: Landforms * Endorheic basin, also known as a sink, alkali flat or sabkha, a desert basin with no outlet which periodically fills with water to form a temporary lake * Dry lake, often called a ''playa'' in the so ...

. It also occurs in dry

cave A cave or cavern is a natural void in the ground, specifically a space large enough for a human to enter. Caves often form by the weathering of rock and often extend deep underground. The word ''cave'' can refer to smaller openings such as sea ...

s and old

mine Mine, mines, miners or mining may refer to: Extraction or digging * Miner, a person engaged in mining or digging *Mining, extraction of mineral resources from the ground through a mine Grammar *Mine, a first-person English possessive pronoun ...

workings as an efflorescence and as a crusty sublimate deposit around

fumarole A fumarole (or fumerole) is a vent in the surface of the Earth or other rocky planet from which hot volcanic gases and vapors are emitted, without any accompanying liquids or solids. Fumaroles are characteristic of the late stages of volcan ...

s. It occurs in

volcanic A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often found where tectonic plates ...

caves on

Mount Etna Mount Etna, or simply Etna ( it, Etna or ; scn, Muncibbeḍḍu or ; la, Aetna; grc, Αἴτνα and ), is an active stratovolcano on the east coast of Sicily, Italy, in the Metropolitan City of Catania, between the cities of Messina a ...

Italy Italy ( it, Italia ), officially the Italian Republic, ) or the Republic of Italy, is a country in Southern Europe. It is located in the middle of the Mediterranean Sea, and its territory largely coincides with the homonymous geographical ...

. It was first described in 1825 for an occurrence in the Espartinas Saltworks,

Ciempozuelos Ciempozuelos () is a municipality in Spain located in the Community of Madrid. The municipality spans across a total area of 49.64 km2 and, as of 1 January 2020, it has a registered population of 25,104. Geography The municipality is located in ...

Madrid Madrid ( , ) is the capital and most populous city of Spain. The city has almost 3.4 million inhabitants and a metropolitan area population of approximately 6.7 million. It is the second-largest city in the European Union (EU), an ...

Spain , image_flag = Bandera de España.svg , image_coat = Escudo de España (mazonado).svg , national_motto = '' Plus ultra'' ( Latin)(English: "Further Beyond") , national_anthem = (English: "Royal March") , ...

and was named for the French chemist,

Louis Jacques Thénard Louis Jacques Thénard (4 May 177721 June 1857) was a French chemist. Life He was born in a farm cottage near Nogent-sur-Seine in the Champagne district the son of a farm worker. In the post-Revolution French educational system , most boys rec ...

(1777–1826). Thénardite crystallizes in the

orthorhombic In crystallography, the orthorhombic crystal system is one of the 7 crystal systems. Orthorhombic lattices result from stretching a cubic lattice along two of its orthogonal pairs by two different factors, resulting in a rectangular prism with ...

system and often forms yellowish, reddish to gray white prismatic crystals although usually in massive crust deposits. Thénardite is

fluorescent Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation. It is a form of luminescence. In most cases, the emitted light has a longer wavelength, and therefore a lower photon energy, th ...

, white in shortwave and yellow-green in longwave UV radiation. In humid conditions, thénardite progressively absorbs water and converts to the deca-hydrated mineral

mirabilite Mirabilite, also known as Glauber's salt, is a hydrous sodium sulfate mineral with the chemical formula Na2SO4·10H2O. It is a vitreous, colorless to white monoclinic mineral that forms as an evaporite from sodium sulfate-bearing brines. It is f ...

, Na₂SO₄ · 10 H₂O.

Gallery

File:Thenardite.png, Crystal structure of thénardite File:Thenardite-321016.jpg, Thénardite, cluster of transparent crystals from Soda Lake, California. Width of cluser is . File:Thenardite-Mirabilite-210778.jpg, Tan thénardite pseudomorphing

crystals from the

Boron, California Boron (formerly Amargo, Baker, Borate, and Kern) is a census-designated place (CDP) in Kern County, California, United States. Boron is southwest of Red Rock Mountain at an elevation of . The population was 2,086 at the 2020 census, up from 2,025 ...

area. Cluster is 6 × 5.5 cm.

References

Bibliography

*Palache, P.; Berman H.; Frondel, C. (1960). "''Dana's System of Mineralogy, Volume II: Halides, Nitrates, Borates, Carbonates, Sulfates, Phosphates, Arsenates, Tungstates, Molybdates, Etc. (Seventh Edition)"'' John Wiley and Sons, Inc., New York, pp. 404-407. Sodium minerals Sulfate minerals Orthorhombic minerals Minerals in space group 70 Cave minerals Evaporite Luminescent minerals {{sulfate-mineral-stub