Strength and toughness are mutually exclusive properties of materials in general and ceramics in particular. Designs found in biological structural materials such as nacre may provide useful guidelines to alleviate this trade-off . Nacre-like alumina, made of brittle constituents only, combines the hardness and strength of standard alumina materials, and comparatively high toughness. This toughness (damage resistance) is achieved mostly by the deviation of cracks along the platelets interface in their brick-and-mortar microstructure . While the deviation of cracks in brick-and-mortar microstructures is well documented, several other toughening mechanisms can exist in biological or bio-inspired materials . Discrete elements modeling (DEM) has been implemented to understand the toughening mechanisms of nacre-like alumina and provide guidelines of microstructural features to implement to improve the damage resistance of these composites . Establishing quantitative links between nano-to microscopic structures and bulk mechanical properties determined in standardized fracture tests requires additional mechanical modeling at various scales and methods that enable imaging the effects of microstructures on the mechanical behavior. For instance, structural defects (such as local misalignments, variable platelet size) of real microstructures spanning few tens of micrometers can be modeled by DEM, which suggests that they may have a significant effect on crack propagation . To validate these results, we developed in situ spectroscopic and scanning electron microscopy (SEM) imaging of stress field and microstructure during a bending test on nacre-like alumina.