For the true color of the shell--- (minus the 'bloom' that adds the pigment layer(s)). look on the inside. The best example that comes to mind is www.eggzy.net where there is a very dark brown egg, with a white inside where there are tick-marks on the inside...(someone keeping track of eggs...lol) Hope it shows up for you.I just read someone on another board saying this is a myth and that there is only white eggs, but I've read studies that the blue is in the shell and that brown is added at a different stage. Do you have any good links to support this?
For the blue eggs--- I can't think of a vivid link that shows the example...but the blue egg shell will be blue on the inside.