How many zeolites are there?
Not too many people know that zeolites represent crystalline solids structures made of silicon, aluminum and oxygen. They form a framework with cavities and channels inside where water and/or small molecules may reside. It is important to know that there are 191 unique zeolite frameworks identified. Needless to say, there are over 40 known naturally occurring zeolite frameworks. Zeolites have an interesting history. They were introduced in 1954 as adsorbents for industrial separations and purifications. Anyway, most of zeolites have been made synthetically. Keep in mind that some of them were made for commercial use.