there was something different in her appearance : in china he had seen her wear elaborate ensembles of gold and rubies ; in istanbul she had been wholly bare of jewels ; but now she wore a very different piece , something like a diadem set around the base of her ruff and hooked cleverly under the edges and the jaw , made of shining steel rather than gold , and secure in the center one enormous diamond nearly the size of a chicken 's egg , which blazed insolently even in the thin morning light .