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Mordenite
Chemical Formula	Ca，Na2，K2Al2Si10O24·7H2O
Species	Silicates
Crystal System	Orthorhombic
Mohs Scale	3-4
Specific Gravity	2.125
Color	Colourless, white, yellowish, pinkish
Streak	White
Luster	Vitreous, Silky
Refractive Index	n = 1.472 - 1.483 n = 1.475 - 1.485 n = 1.477 - 1.487
Diaphaneity	Transparent, Translucent
Cleavage	Perfectperfect on distinct on
Fracture	Irregular/Uneven
Crystal Habit：Prismatic crystals, acicular to fine fibrous, radiating groups, cottony aggregates, compact, porcelaneous.
Geological Setting：Veins and amygdaloids in igneous rocks.

Mordenite is a zeolite mineral with the chemical formula, (Ca, Na₂, K₂)Al₂Si₁₀O₂₄·7H₂O. According to Ullmann's Encyclopedia of Industrial Chemistry (2005), it is one of the six most abundant zeolites and is used commercially.

It was first described in 1864 by Henry How. He named it after the small community of Morden, Nova Scotia, Canada, along the Bay of Fundy, where it was first found.

Mordenite is orthorhombic. It crystallizes in the form of fibrous aggregates, masses, and vertically striated prismatic crystals. It may be colorless, white, or faintly yellow or pink. It has Mohs hardness of 5 and a density of 2.1 g/cm³. When it forms well developed crystals they are hairlike; very long, thin, and delicate.

Mordenite’s molecular structure is a framework containing chains of five-membered rings of linked silicate and aluminate tetrahedra (four oxygen atoms arranged at the points of a triangular pyramid about a central silicon or aluminium atom). Its high ratio of silicon to aluminum atoms makes it more resistant to attack by acids than most other zeolites.

Mordenite is one of the most abundant zeolites in altered volcanic deposits; it is found in volcanic rock such as rhyolite, andesite, and basalt. It is associated with other zeolites such as stilbite and heulandite. Good examples have been found in Iceland, India, Italy, Oregon, Washington, and Idaho. It is also found in marine sediments, as in the Ural Mountains and in dikes where water has attacked and altered volcanic glasses, as on the Isle of Arran in Scotland.

Use

Synthetic Mordenite is used as a catalyst in the petrochemical industry for the acid-catalyzed isomerisation of alkanes and aromatics.