Mendozite
Encyclopedia
Mendozite is a sulfate
mineral, one of the alum
series, with formula NaAl(SO4)2·11H2O. It is a hydrated form of sodium aluminium sulfate (soda alum).
It was discovered in western Argentina
in 1868, probably near San Juan
. The exact location has been lost, but was described as "San Juan, near Mendoza
", and it is the latter city that give the mineral its name. It occurs in evaporites, presumably from the oxidation of sulfide mineral
s in the presence of clay
s. It is very soluble in water, and so can only be found in dry regions: however, in can still effloresce
(lose water of crystallisation) in extremely arid climates, altering to tamarugite
(the hexahydrate).
Sulfate
In inorganic chemistry, a sulfate is a salt of sulfuric acid.-Chemical properties:...
mineral, one of the alum
Alum
Alum is both a specific chemical compound and a class of chemical compounds. The specific compound is the hydrated potassium aluminium sulfate with the formula KAl2.12H2O. The wider class of compounds known as alums have the related empirical formula, AB2.12H2O.-Chemical properties:Alums are...
series, with formula NaAl(SO4)2·11H2O. It is a hydrated form of sodium aluminium sulfate (soda alum).
It was discovered in western Argentina
Argentina
Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...
in 1868, probably near San Juan
San Juan, Argentina
San Juan is the capital city of the Argentine province of San Juan in the Cuyo region, located in the Tulúm Valley, west of the San Juan River, at above mean sea level, with a population of around 112,000 as per the ....
. The exact location has been lost, but was described as "San Juan, near Mendoza
Mendoza, Argentina
Mendoza is the capital city of Mendoza Province, in Argentina. It is located in the northern-central part of the province, in a region of foothills and high plains, on the eastern side of the Andes. As of the , Mendoza's population was 110,993...
", and it is the latter city that give the mineral its name. It occurs in evaporites, presumably from the oxidation of sulfide mineral
Sulfide mineral
The sulfide minerals are a class of minerals containing sulfide as the major anion. Some sulfide minerals are economically important as metal ores. The sulfide class also includes the selenides, the tellurides, the arsenides, the antimonides, the bismuthinides, the sulfarsenides and the sulfosalts...
s in the presence of clay
Clay
Clay is a general term including many combinations of one or more clay minerals with traces of metal oxides and organic matter. Geologic clay deposits are mostly composed of phyllosilicate minerals containing variable amounts of water trapped in the mineral structure.- Formation :Clay minerals...
s. It is very soluble in water, and so can only be found in dry regions: however, in can still effloresce
Efflorescence
In chemistry, efflorescence is the loss of water of crystallization from a hydrated or solvated salt to the atmosphere on exposure to air.-Examples:...
(lose water of crystallisation) in extremely arid climates, altering to tamarugite
Tamarugite
Tamarugite is a colorless monoclinic sulfate mineral.Also known as lapparentite.-References:*...
(the hexahydrate).