In situ fluorescence mapping of stress and SEM imaging during mechanical tests prove useful to identify local mechanisms and microstructural features that contribute to toughening in these bioinspired composites. Future improvements will focus on measurements that can be combined on the same sample and use the orientation information provided by EBSD to locally analyze the stress from the scale of the individual components (here the alumina platelets) to the scale of the aggregate (platelets bundles) and of the bulk sample. Besides using fluorescence, stress can also be characterized using Raman spectroscopy in non-luminescent materials. This approach could be applied to other advanced ceramics like zirconia, or natural ceramics like apatite and calcium carbonates .