Picromerite (synonyms: schoenite, schönite) is a mineral from the class of hydrous

sulfates The sulfate or sulphate ion is a polyatomic anion with the empirical formula . Salts, acid derivatives, and peroxides of sulfate are widely used in industry. Sulfates occur widely in everyday life. Sulfates are salts of sulfuric acid and many a ...

lacking additional anions, and containing medium to large cations according to the

Nickel–Strunz classification Nickel–Strunz classification is a scheme for categorizing minerals based upon their chemical composition, introduced by German mineralogist Karl Hugo Strunz (24 February 1910 – 19 April 2006) in his ''Mineralogische Tabellen'' (1941). The 4th ...

Etymology

The name comes from the Greek words πικρός ikrosfor "bitter" and μέρος

eros In Greek mythology, Eros (, ; grc, Ἔρως, Érōs, Love, Desire) is the Greek god of love and sex. His Roman counterpart was Cupid ("desire").''Larousse Desk Reference Encyclopedia'', The Book People, Haydock, 1995, p. 215. In the ear ...

for "part", and relates to the bitter taste of the mineral.

Occurrence

Picromerite is found on comparatively few places, currently (2015) only about 40 localities are known. It was first identified in active volcanic fumaroles on

Mount Vesuvius Mount Vesuvius ( ; it, Vesuvio ; nap, 'O Vesuvio , also or ; la, Vesuvius , also , or ) is a somma-stratovolcano located on the Gulf of Naples in Campania, Italy, about east of Naples and a short distance from the shore. It is one of ...

Arcangelo Scacchi Arcangelo Scacchi (9 February 1810 – 11 October 1893) was an Italian physician, mineralogist, malacology, malacologist, and naturalist. He served as a professor of mineralogy at the University of Naples Federico II, University of Naples. Between ...

in 1855 and has also been found in volcanic deposits on Mount Etna and on

Hawai'i Hawaii ( ; haw, Hawaii or ) is a state in the Western United States, located in the Pacific Ocean about from the U.S. mainland. It is the only U.S. state outside North America, the only state that is an archipelago, and the only ...

. It is more commonly found in the

kainite Kainite ( or ) (KMg(SO4)Cl·3H2O) is an evaporite mineral in the class of "Sulfates (selenates, etc.) with additional anions, with H2O" according to the Nickel–Strunz classification. It is a hydrated potassium-magnesium sulfate-chloride, natura ...

zones of some marine salt deposits, among them salt mines in

Thuringia Thuringia (; german: Thüringen ), officially the Free State of Thuringia ( ), is a state of central Germany, covering , the sixth smallest of the sixteen German states. It has a population of about 2.1 million. Erfurt is the capital and lar ...

Lower Saxony Lower Saxony (german: Niedersachsen ; nds, Neddersassen; stq, Läichsaksen) is a German state (') in northwestern Germany. It is the second-largest state by land area, with , and fourth-largest in population (8 million in 2021) among the 16 ...

and

Saxony-Anhalt Saxony-Anhalt (german: Sachsen-Anhalt ; nds, Sassen-Anholt) is a state of Germany, bordering the states of Brandenburg, Saxony, Thuringia and Lower Saxony. It covers an area of and has a population of 2.18 million inhabitants, making it th ...

(Germany), near Hall in Tirol,

Hallstatt Hallstatt ( , , ) is a small town in the district of Gmunden, in the Austrian state of Upper Austria. Situated between the southwestern shore of Hallstätter See and the steep slopes of the Dachstein massif, the town lies in the Salzkammergut ...

and

Bad Ischl Bad Ischl (Austrian German ) is a spa town in Austria. It lies in the southern part of Upper Austria, at the Traun River in the centre of the Salzkammergut region. The town consists of the Katastralgemeinden ''Ahorn'', ''Bad Ischl'', ''Haide ...

(Austria), near

Whitby Whitby is a seaside town, port and civil parish in the Scarborough borough of North Yorkshire, England. Situated on the east coast of Yorkshire at the mouth of the River Esk, Whitby has a maritime, mineral and tourist heritage. Its East Clif ...

(UK), and in the Carlsbad Potash District (New Mexico), also on salt lakes in western China. Picromerite can also form in sulfate-rich hydrothermal ore deposits and is found in slag heaps of some ore and coal mines. Picromerite is often accompanied by

anhydrite Anhydrite, or anhydrous calcium sulfate, is a mineral with the chemical formula CaSO4. It is in the orthorhombic crystal system, with three directions of perfect cleavage parallel to the three planes of symmetry. It is not isomorphous with the ...

epsomite Epsomite, Epsom salt, or magnesium sulfate heptahydrate, is a hydrous magnesium sulfate mineral with formula MgSO4·7H2O. Epsomite crystallizes in the orthorhombic system as rarely found acicular or fibrous crystals, the normal form is as massiv ...

halite Halite (), commonly known as rock salt, is a type of salt, the mineral (natural) form of sodium chloride ( Na Cl). Halite forms isometric crystals. The mineral is typically colorless or white, but may also be light blue, dark blue, purple, p ...

, hohmannite,

, metasideronatrite and metavoltine, depending on the locality.

Properties

Picromerite dehydrates in dry air, and crystals then show dull, spherical dehydration zones. Progressive dehydration leads to

leonite Leonite is a hydrated double sulfate of magnesium and potassium. It has the formula K2SO4·MgSO4·4H2O. The mineral was named after Leo Strippelmann, who was director of the salt works at Westeregeln in Germany. The mineral is part of the blodit ...

References

External links

* {{cite web , url = http://rruff.geo.arizona.edu/AMS/result.php?mineral=Picromerite , publisher = American Mineralogist Crystal Structure Database , title = Picromerite Potassium minerals Monoclinic minerals Minerals in space group 14 Magnesium minerals Sulfate minerals Evaporite