The material investigated in the current study consists of ceramic (magnetite) nano-particles. These are first surface-functionalized with very thin layer of oleic acid and then arranged in a crystallographic structure by self-assembly. After some heat treatment, which improves both stiffness and strength due to crosslinking of the organic material, the material is tested by nanoindentation. It turns out that (a) the material has a strong time-dependent, i.e., viscous, behavior, and (b) the scatter of the force displacement curve is aggravatingly high. We have to tackle these challenges by employing a generalized Maxwell material model including one elasto-plastic branch for the inelasticity and time dependence [1] and including a rather low size variation of the nano-particles for the simulation of the scatter [2]. The identification of the composite’s material properties from nanoindentation tests and the subsequent determination of the constituents’ properties, of which particularly the viscous behavior of the organic material is crucial, using a top-down approach are the main tasks presented here. While the material’s fracture toughness is by a factor of magnitude higher than a pure ceramic of which it mainly consists of, the toughness behavior needs to be further increased by a second hierarchy level, for which supraparticles of the material described above are embedded in an Epoxy matrix. First simulation results and comparison with experiments are shown also for the second hierarchy level.