Efremovite
Encyclopedia
Efremovite is a rare ammonium
sulfate mineral
with the chemical formula: (NH4)2Mg2(SO4)3. It is a white to gray cubic
mineral. This anhydrous sulfate occurs as constituent in sulfate crust
s of burning coal
dumps. It is hygroscopic and when exposed to humid air it slowly converts to the hydrate
form, boussingaultite
.
It was first described in 1989 for an occurrence in the Chelyabinsk coal basin, Southern Urals, Russia
. It was named for Russian geologist Ivan Antonovich Yefremov (1907–1972). It has also been reported from several coal mining areas across Europe. It occurs in association with native sulfur, kladnoite, mascagnite
, and boussingaultite
.
Ammonium
The ammonium cation is a positively charged polyatomic cation with the chemical formula NH. It is formed by the protonation of ammonia...
sulfate mineral
Sulfate mineral
The sulfate minerals are a class of minerals which include the sulfate ion within their structure. The sulfate minerals occur commonly in primary evaporite depositional environments, as gangue minerals in hydrothermal veins and as secondary minerals in the oxidizing zone of sulfide mineral deposits...
with the chemical formula: (NH4)2Mg2(SO4)3. It is a white to gray cubic
Cubic crystal system
In crystallography, the cubic crystal system is a crystal system where the unit cell is in the shape of a cube. This is one of the most common and simplest shapes found in crystals and minerals....
mineral. This anhydrous sulfate occurs as constituent in sulfate crust
Sulfate crust
Suasdlsdjety godovikovite and millosevichite. The outer zone can easily be hydrated giving rise to minerals like tschermigite and alunogen. The zone forms due to interaction with hot coal-derived gases with the "sterile" material Suasdlsdjety godovikovite and millosevichite. The outer zone can...
s of burning coal
Coal
Coal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers or veins called coal beds or coal seams. The harder forms, such as anthracite coal, can be regarded as metamorphic rock because of later exposure to elevated temperature and pressure...
dumps. It is hygroscopic and when exposed to humid air it slowly converts to the hydrate
Hydrate
Hydrate is a term used in inorganic chemistry and organic chemistry to indicate that a substance contains water. The chemical state of the water varies widely between hydrates, some of which were so labeled before their chemical structure was understood....
form, boussingaultite
Boussingaultite
Boussingaultite is a rare sulfate mineral of the chemical formula: 2Mg2·6. The formula of boussingaultite is that of Tutton's salts type. It was originally described from geothermal fields in Tuscany, Italy, where it occurs together with its iron analogue mohrite, but is more commonly found on...
.
It was first described in 1989 for an occurrence in the Chelyabinsk coal basin, Southern Urals, Russia
Russia
Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...
. It was named for Russian geologist Ivan Antonovich Yefremov (1907–1972). It has also been reported from several coal mining areas across Europe. It occurs in association with native sulfur, kladnoite, mascagnite
Mascagnite
Mascagnite is a rare ammonium sulfate mineral 2SO4. It crystallizes in the orthorhombic system typically forming as stalactitic masses exhibiting good cleavage. It is soft and water soluble...
, and boussingaultite
Boussingaultite
Boussingaultite is a rare sulfate mineral of the chemical formula: 2Mg2·6. The formula of boussingaultite is that of Tutton's salts type. It was originally described from geothermal fields in Tuscany, Italy, where it occurs together with its iron analogue mohrite, but is more commonly found on...
.