effective medium theory for noble metals

hello every one
i want to use the effective medium theory for structure containing small noble nano particle such as gold embedded in a dielectric medium and spatially i want to use Maxwell-garnet theory
i studied many paper about Maxwell garnet but for noble metals i don't know the answer please help me

this particles are nano particles that their size are small compere to the wavelength and this particles embedded in dielectric medium so there are surface plasmon polaritons in the interface, i mean plasmonic structure and this structure is in the presence of an external magnetic field so i want to use effective medium theory in an-isotropic media to calculate the tensor dielectric constant of gold and i studied many reference for that case but for noble metals when localized surface plasmons are excited and we have resonance , i don't know how input this condition to effective medium maxwell garnet formula if you have reference about that i really appreciate you