Melamine is a common organic molecule based on a six-sided ring; this unit typically connects with itself or other organic species to form layered crystal structures, which then exhibit strongly anisotropic properties. For example, the materials may be very strong in the plane of the layers but extremely weak perpendicular to the layers. To date, high-pressure studies of melamine designed to probe this anisotropy have produced contradictory results. Many of them see evidence of a change in crystal structure - a phase transition - at comparatively low pressures of 1 GPa, others see no changes at all. Unfortunately, the data used to arrive at these conclusions are often quite poor.My objective is to collect high-quality data from melamine up to 6-7 GPa in order to identify any high-pressure polymorphs and to better characterise the elastic anisotropy.