The future of mineralogical crystallography: Expanding horizons in the 21 ^st century

Abstract Mineralogical crystallography has evolved from the geometric and observational studies of the eighteenth century to a dynamic, predictive science capable of probing matter at atomic and nano-scales. Contemporary advances, including ultrafast X-ray free-electron lasers, high-pressure diamond anvil cells, cryo- and environmental electron microscopy, and multimodal in situ techniques, now permit real-time observation of mineral transformations under extreme conditions. Coupled with computational modelling and predictive simulations, these methods are transforming crystallography into an integrative, interdisciplinary discipline with applications ranging from Earth and planetary sciences to materials engineering. This essay explores technological innovations and emerging frontiers of mineralogical crystallography, highlighting its enduring role in revealing the hidden architectures of matter and guiding the exploration of both natural and synthetic materials.