All I can say about the color/look of the eggs is don't throw them out until you are absolutely sure they are no good. I have seen some pretty awful looking eggs hatch!
Also with most gecko eggs, water dragon, cone heads, some turtle eggs that I have seen, the egg glows reddish/pinkish when a fine beam from a maglite is shone on the egg from the side. I've never candled a chameleon's egg...so I can't really say what it looks like. Just don't turn the egg while you are candling it...it might cause problems.
Generally, fertile eggs are very white and larger than infertile eggs....but there are always exceptions regarding the color. Infertile eggs will usually mold and shrivel up in a few days/weeks after they are laid. Eggs that die during the incubation process also shrivel up and mold as a rule.
I can tell you one thing....its really a thrill to see the baby moving around inside an egg! Its almost like an ultrasound of a human baby....only clearer. You can usually see feet, tail, head outlines. I don't know if the light bothers the baby or can cause any problems, so I do it quickly and not often....just in case.