Zeolite

any of a group of hydrated silicates of aluminum with alkali metals, commonly occurring as secondary minerals in cavities in basic volcanic rocks: used for their molecular sieve properties because they undergo dehydration with little or no change in crystal structure.
historical examples

chambers’s twentieth century dictionary (part 4 of 4: s-z and supplements) various
in the arctic seas francis leopold mcclintock
drake’s road book of the grand junction railway james drake
the new gresham encyclopedia. vol. 1 part 2 various

noun
any of a large group of gl-ssy secondary minerals consisting of hydrated aluminium silicates of calcium, sodium, or pot-ssium: formed in cavities in lava flows and plutonic rocks
any of a cl-ss of similar synthetic materials used in ion exchange and as selective absorbents see molecular sieve
zeolite
(zē’ə-līt’)
any of a family of hydrous aluminum silicate minerals, whose molecules enclose cations of sodium, pot-ssium, calcium, strontium, or barium. zeolites are usually white or colorless, but they can also be red or yellow. they are characterized by their easy and reversible loss of water of hydration. they usually occur within cavities in basalt.