Aerinite () is a bluish-purple

inosilicate Silicate minerals are rock-forming minerals made up of silicate groups. They are the largest and most important class of minerals and make up approximately 90 percent of Earth's crust. In mineralogy, silica (silicon dioxide, ) is usually consid ...

mineral. It crystallizes in the

monoclinic In crystallography, the monoclinic crystal system is one of the seven crystal systems. A crystal system is described by three vectors. In the monoclinic system, the crystal is described by vectors of unequal lengths, as in the orthorhombic s ...

system and occurs as fibrous or compact masses and coatings. It has a dark, vitreous luster, a

specific gravity Relative density, or specific gravity, is the ratio of the density (mass of a unit volume) of a substance to the density of a given reference material. Specific gravity for liquids is nearly always measured with respect to water (molecule), wa ...

of 2.48 and a

Mohs hardness The Mohs scale of mineral hardness () is a qualitative ordinal scale, from 1 to 10, characterizing scratch resistance of various minerals through the ability of harder material to scratch softer material. The scale was introduced in 1812 by th ...

of 3. It is a low-temperature

hydrothermal Hydrothermal circulation in its most general sense is the circulation of hot water (Ancient Greek ὕδωρ, ''water'',Liddell, H.G. & Scott, R. (1940). ''A Greek-English Lexicon. revised and augmented throughout by Sir Henry Stuart Jones. with th ...

phase occurring in zeolite facies alteration of dolerites. Associated minerals include

prehnite Prehnite is an inosilicate of calcium and aluminium with the formula: Ca2Al(AlSi3O10)(OH)2. Limited Fe3+ substitutes for aluminium in the structure. Prehnite crystallizes in the orthorhombic crystal system, and most often forms as stalactitic or bo ...

scolecite Scolecite is a tectosilicate mineral belonging to the zeolite group; it is a hydrated calcium silicate, Ca Al2 Si3 O10· 3H2O. Only minor amounts of sodium and traces of potassium substitute for calcium. There is an absence of barium, strontium, ...

and

mesolite Mesolite is a tectosilicate mineral with formula Na2 Ca2( Al2 Si3 O10)3·8 H2O. It is a member of the zeolite group and is closely related to natrolite which it also resembles in appearance. Mesolite crystallizes in the orthorhombic system and t ...

. Its name comes from a

Greek Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. **Proto-Greek language, the assumed last common ancestor ...

root In vascular plants, the roots are the organs of a plant that are modified to provide anchorage for the plant and take in water and nutrients into the plant body, which allows plants to grow taller and faster. They are most often below the sur ...

"aerinos," meaning "atmosphere" or "sky blue". It was first described by Lasaulx (1876) from a specimen in the Wroclaw museum that was obtained in Aragon, Spain. In 1882, the geologist Luis Mariano Vidal found the mineral in situ in Caserras del Castillo, a locality that currently belongs to the municipality of Estopiñán del Castillo, in Huesca (Spain).

Deposits and uses

Aerinite is a rare mineral. It has been found in several deposits in the Spanish Pyrenees of Huesca and Lleida, as in Estopiñán del Castillo, Camporrells, Juseu and Tartareu. In France, the site is important from St. Pendelon, in the Landes. Aerinite was used as a blue pigment in Romanesque paintings in many churches in the Spain, and also in some French, including the most famous of them, the Pantocrator in the church of San Clemente de Tahull.

References

{{reflist Calcium minerals Iron minerals Magnesium minerals Inosilicates Carbonate minerals Trigonal minerals Minerals in space group 158