Optical properties of a three-dimensional composite medium consisting of an amplifying matrix with inclusion of silver
nanoparticles of various shapes are investigated theoretically. Considering the case of an effective refractive index equal
to one, condition for a transparent material, the amplification coefficient needed for compensating the losses is studied. It
is shown that for the composite material with ellipsoidal inclusions the required gain coefficient is significantly less that
for a composite medium with spherical inclusions.