Whilst orientation relationships between twin or polytype domains can be elucidated using 3D-ED, information solely in reciprocal space is limited in its ability to describe the spatial distribution, the number of these domains (although calculating twin fraction is possible and well-established ), or the nature of associated interfaces. Here, 4D-STEM is used to visualise the xanthine microstructure directly. Particles typically appeared blocky in morphology, often with a pair of parallel facets and a pair of less well-defined edges (such as in Figure ). The resulting 4D dataset is analysed in two ways: (1) summed diffraction patterns from sub-regions of the crystal are used to understand structural variations and orientation changes; (2) virtual dark field images (VDFs) are formed using the intensity from a specific Bragg reflection mapped across the region of interest; this highlights in particular which areas are at the Bragg condition for that particular reflection and thus can highlight twins and planar disorder.