Sublimation is a fundamental phase transition that has a profound impact on both natural phenomena and advanced manufacturing technologies. Although great strides have been made in the study of ice growth from melt and vapour, little consideration has been given to the effect of sublimation on the morphological features that develop in the ice microstructure. In this experimental study, we demonstrate the effect of vapour pressure on the mesoscopic faceting observed and show that a vapour pressure-specific wavelength characterises the periodic features that arise during sublimation. The ability to control the length scale of these features not only provides us with new insights on the mesoscopic roughness of ice crystals, but also presents the potential to exploit this effect in a plethora of applications from comet dating to ice-templated tissue engineering scaffolds