Class : Silicates
    Subclass : Tectosilicates
    Crystal system : Monoclinic
    Chemistry : (Ca,K,Na)₃Al₃Si₁₅O₃₆ 11.5H₂O
    Rarity : Rare to uncommon

Clinoptilolite is a mineral from the zeolite group, chemically very close to heulandite, of which it was long considered a variety. Its name is linked to its monoclinic crystal system and its chemical similarity to ptilolite. It is found in the cavities of andesitic to rhyolitic lavas, which have provided the most beautiful crystals, as a product of devitrification of volcanic glasses, sometimes in Alpine clefts and more rarely in sedimentary domains. It appears in lamellar crystals, generally small (1 cm), or in finely grained masses, colorless or rarely orange-red. Zeolites have important industrial applications, based on their channel structure which allows molecular sieving (used in petroleum cracking), the presence of water which can be evacuated by heating (hydration and dehydration properties ), the existence of weakly bonded cations which give them very important ion exchange properties. To satisfy these industrial needs, artificial zeolites are produced in large quantities, clinoptilolite with chabazite and heulandite or stilbite being the only ones sufficiently abundant and pure to constitute exploitable deposits.

Main photo : Clinoptilolite from Cape Lookout Quarry, Oregon, USA © Daniel Russell

No twin known for this mineral species.

Due to its occasionally sedimentary deposits, clinoptilolite can line the cavities of fossil organisms, this is the case at Bushy Point near Kaipara Harbor (New Zealand) where it has been reported on fossil marine gastropods.

No fake identified for this mineral species.