In the tectosilicate
structure of quartz, in which there is no center of symmetry, enantiomorphism results from how the tetrahedral Si[O.
In the past, zeolites were limited to tectosilicates
and tetrahedrons containing aluminum and silicon.
In one way the organization here is conventional, the chapters moving in Dana order from native elements through tectosilicates
, to end at last with opal, a non-crystalline "mineraloid.
Nitric acid-extractable K represents exchangeable K plus some K extracted from within phyllosilicate and tectosilicates
These data are consistent with a dissolution-precipitation process in tectosilicates
, but it is very similar to that of the montmorillonite transformation.
Structure of tectosilicates is formed from tetrahedrons mutually linked by all their oxygen atoms.
The zeolite minerals belong also to tectosilicates but in contrast with Cs-AS, ANALC and ORT they form complicated structure with relative big cavities among their tetrahedrons.