Hello there!
That's a good question! Ameraucana is a breed that lays a pale blue egg. They are just lovely. If you really want to see what a true Ameraucana looks like, check out the Ameraucana Breeders's Club. They have TONS of pics of every color. Just google it. Ameraucanas have very think hackle feathers, and they have muffs and a beard. They are lovely.
Then there's the Araucana, which also lays a pale blue egg, and it's quite different. There are various colors, and breeders are always trying for the perfect specimen, which is tufted and rumpless. They're really neat looking birds. Difficult to breed to the standard, because there is a fatal genetic combination.....I won't get into that though.
Then EEs, are Easter Eggers, and they are truly a mutt, but they usually have some Ameraucana in there somewhere, and they often lay an olive green colored egg, or a pale, sea foam green egg, and some even lay the pale blue egg. EEs are not a breed recognized by the APA, like the other two. Hatcheries that list Ameraucana or Araucana, are usually truly selling the EEs.
EEs by the way, are really beautiful too, just like their pure bred relatives!
Hope this helps!