Figure 5.

Real-space PDFs or G(r) for the five natural samples compared to experimental PDFs for Fh and amorphous SiO₂ references. (A) The strong attenuation in the features of the PDFs with increasing r for the natural samples indicates smaller coherent scattering domain (CSD) sizes and increased disorder relative to synthetic Fh. Sample Ula Nui-B shows more structure at higher r due to birnessite phase impurity. (B) Comparison of the short-range order for these samples. Similarities between natural samples and synthetic references for Fh and amorphous silica are highlighted.