Statistical analyses of the zeolites clinoptilolite and heulandite

Cluster analysis showed that at least five compositional subgroups exist within the heulandite family of zeolites. The two extreme members of these five groups are the traditional heulandites and clinoptilolites. At a coarser level of clustering, two subgroups, clinoptilolite and heulandite, are evident. As shown by discriminant analysis, the most important compositional variable distinguishing all these groups is calcium. From principal components analysis, it was found that the c cell dimensions of the heulandite family of zeolites varies directly with aluminum and inversely with silicon. The a cell dimension and the β angle seem to vary inversely with the iron content. The b cell dimension may vary inversely with iron and aluminum and directly with silicon.