Mesolite is a tectosilicate mineral with formula Na2Ca2Si9Al6O30·8H2O. It is a member of the zeolite group and the natrolite subgroup,[4] also resembling natrolite in appearance.
Mesolite crystallizes in the orthorhombic system and typically forms fibrous, acicular prismatic crystals or masses.[3] Radiating sprays of needlelike crystals are not uncommon. It is vitreous in luster and clear to white in color. It has a Mohs hardness of 5 to 5.5 and a low specific gravity of 2.2 to 2.4. The refractive indices are nα=1.505 nβ=1.505 nγ=1.506.
Occurrence
It was first described in 1816 for an occurrence in the Cyclopean Islands near Catania, Sicily.[5] From the Greek mesos, "middle", as its composition lies between natrolite and scolecite.[4][5] Like other zeolites, mesolite occurs as void fillings in amygdaloidal basalt also in andesites and hydrothermal veins.[3]
Images
-
Mesolite -
"Puff ball" of mesolite in a basaltic vug -
Mesolite often forms in fibrous crystals -
A pocket of hairlike acicular crystals of mesolite growing off thomsonite -
Fibrous crystal sample retrieved from caverns near Pune, India
References
- ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
- ^ Mineralienatlas
- ^ a b c Handbook of Mineralogy
- ^ a b c Mindat.org
- ^ a b c Webmineral data