Most members of this group result from secondary processes by which precursor minerals have been altered. Extensive zeolite deposits appear in felsic volcanic ash flow sheets and associated volcanic rocks, occurring most commonly in vesicles or void spaces. The composition of zeolites depends on that of the protolith . A quartz diorite and quartz monzonite intrusion into a limestone, showing zones of contact metamorphism. The structure of zeolite ZSM-5, which is used as a molecular sieve.
Zeolites are extremely useful economically.
Loosely bound M and D cations in zeolite voids and channels can be exchanged for other cations. For additional information about the zeolite group, including 3D structure models, see the Zeolite Links page.