We appreciate the interest from de Jong (2024, this issue) in our study on the structure of opal-A using synchrotron X-ray diffraction (XRD) and pair distribution function (PDF) analysis (Lee et al. 2022). Several comments were made by de Jong (2024) on the strengths and weaknesses of PDF analysis, the existence of 4- and 8-membered silica rings in the opal-A structure, and the usefulness of opal phase transitions as stratigraphic markers. Here, we shall address these comments in turn.

X-ray PDF analysis is one of the main techniques employed in Lee et al. (2022), and it...

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