The set of parameters necessary to capture inclusion quantum mechanical size, shape and interfacial effects are considered in detail. We assess the transferability of these parameters to a range of inclusion types for mixtures of MgO and nanoscale Ag inclusions. Along the way, we propose a definition of the continuum geometry based on Bader volumes calculated from quantum dynamics, define a procedure for fitting FEM parameters to quantum results, and validate the use of a continuum approach to the polarizability of isolated silver nanoparticles to motivate a similar approach for nanocomposites. Herein, the method devised by Hally and Paci (Ref. ) is used to generate quantum mechanical data for silver inclusions in MgO matrices. Based on this quantum data, we parameterize a continuum model whose permittivity, ε, can be calculated via the FEM. The model is then used to investigate the effects of the shape and loading of inclusions on the permittivities of Ag/MgO nanocomposites. Paci calculated the relative permittivity of bulk MgO to be ε r = 9.3. ε r = ε/ε 0 , where ε 0 is the permittivity of free space. The relative permittivity of an Ag 8 /MgO nanocomposite was also determined, and was found to be 11.9, for an inclusion atomic loading of 3.7 %. To explore the loading dependence of the permittivity, we examined two additional nanocomposites, comprised of MgO supercells of 64 and 512 atoms and Ag 8 inclusions.