To examine the distributions of K and G, Gaussian kernel density estimates were calculated as displayed in Figure with corresponding interquartile ranges. Zeolite frameworks belonging to the PCOD2 database are observed to largely have K and G moduli less than 40 GPa and 30 GPa, respectively. The skew of this distribution suggests most hypothetical structures are significantly less stiff and shear-resistant than the known zeolite frameworks recognised by the IZA.