Mesolite is a

tectosilicate 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 with formula Na₂ Ca₂( Al₂ Si₃ O₁₀)₃·8 H₂O. It is a member of the

zeolite Zeolites are microporous, crystalline aluminosilicate materials commonly used as commercial adsorbents and catalysts. They mainly consist of silicon, aluminium, oxygen, and have the general formula ･y where is either a metal ion or H+. These pos ...

group and is closely related to

natrolite Natrolite is a tectosilicate mineral species belonging to the zeolite group. It is a hydrated sodium and aluminium silicate with the formula . The type locality is Hohentwiel, Hegau, Germany. It was named natrolite by Martin Heinrich Klapro ...

which it also resembles in appearance. Mesolite crystallizes in the orthorhombic system and typically forms fibrous, acicular prismatic crystals or masses. Radiating sprays of needlelike crystals are not uncommon. It is vitreous in luster and clear to white in color. It has 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 5 to 5.5 and a low

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 2.2 to 2.4. The

refractive indices In optics, the refractive index (or refraction index) of an optical medium is a dimensionless number that gives the indication of the light bending ability of that medium. The refractive index determines how much the path of light is bent, or ...

are nα=1.505 nβ=1.505 nγ=1.506.

Occurrence

It was first described in 1816 for an occurrence in the

Cyclopean Islands The Cyclopean Isles (Italian: ''Isole Ciclopi''), noted for their rows of basaltic columns piled one above another, lie not far from Mount Etna off the eastern coast of Sicily in the Mediterranean Sea. Geology Formed about 500,000 years ago, the ...

near

Catania Catania (, , Sicilian and ) is the second largest municipality in Sicily, after Palermo. Despite its reputation as the second city of the island, Catania is the largest Sicilian conurbation, among the largest in Italy, as evidenced also by ...

Sicily (man) it, Siciliana (woman) , population_note = , population_blank1_title = , population_blank1 = , demographics_type1 = Ethnicity , demographics1_footnotes = , demographi ...

. From the Greek ''mesos'', "middle", as its composition lies between

and

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, ...

. Like other zeolites, mesolite occurs as void fillings in amygdaloidal

basalt Basalt (; ) is an aphanite, aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the planetary surface, surface of a terrestrial ...

also in

andesite Andesite () is a volcanic rock of intermediate composition. In a general sense, it is the intermediate type between silica-poor basalt and silica-rich rhyolite. It is fine-grained (aphanitic) to porphyritic in texture, and is composed predomi ...

s and

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 ...

veins Veins are blood vessels in humans and most other animals that carry blood towards the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are the pulmonary and umbilical veins, both of which carry oxygenated b ...

Images

File:Mesolite (6911826414).jpg, Mesolite File:Mesolite-Quartz-238750.jpg, "Puff ball" of mesolite in a basaltic vug File:Mesolite spikes.jpg, Mesolite often forms in fibrous crystals File:Mesolite-Thomsonite-44359.jpg, A pocket of hairlike acicular crystals of mesolite growing off thomsonite File:Mesolite, fibrous crystals.jpg, Fibrous crystal sample retrieved from caverns near

Pune Pune (; ; also known as Poona, (List of renamed Indian cities and states#Maharashtra, the official name from 1818 until 1978) is one of the most important industrial and educational hubs of India, with an estimated population of 7.4 million ...

, India

References

Mineral Galleries
Sodium minerals Calcium minerals Aluminium minerals Zeolites Orthorhombic minerals Minerals in space group 43 {{silicate-mineral-stub