Multilayer systems comprising either Al or Cu bonded to sapphire have been used to evaluate stress redistribution effects around cracks, caused by slip in the metal. Single precracks have been introduced into the outermost sapphire layer and strain distributions measured around those cracks upon loading. Both moire interferometry and (Cr 3 + ) fluorescence piezospectroscopy have been used for that purpose. Finite element calculations of the plastic zone size, L s , the crack opening displacement, δ, and the strains have been made, with the yield strengths of the metals, σ o , regarded as unknowns. Comparison of L s or δ with the measurements establishes σ o . Once the relevant yield strengths have been determined, the calculated stresses and strains (as redistributed by slip in the metal layer) are found to be in reasonable correspondence with the values measured by either moire interferometry or piezospectroscopy. Some small discrepancies remain, which have yet to be explained.