Stupid Question

This has bothered me for some time and finally I've decided to try to get a resolution......I've often heard/read mulder's eyes described as hazel. How do people on the list define hazel eyes? I've always been led to believe that hazel was descriptive of eyes which were essentially brown, but with the capacity to alter and become green depending on mood, external stimuli, or whatever. I've looked really hard at DD's eyes and they just seem sort of blue or grey-blue to me. Is this just another fanfic convention or does hazel mean something different to most people? Sarah Michelle Geller {Buffy} has what I would describe as quintessentially hazel eyes and Peter Wingfield (Methos)has eyes that I've seen go green in one memorable scene in HL, but in general are usually amber brown. I would also describe his eyes as hazel. So help me please, what colour are DD's eyes. I mean really.