For the Firefly render, I am assuming that there is some self glowing going on that is causing no shadows from the tiara. Try a different lighting arrangement, in particular, IDL to see if there is a change. In the Superfly render, there is some shadowing happening from the tiara but the Ambient Occlusion is very subtle, the tiara may be too close to the skin. Again, try another lighting arrangement to see if it corrects the render.