Edit: since there was a post in between this is in reply to karenmyrrh.
There are three breeds that lay colored eggs and due to lack of education they get confused for one another and sold interchangably all the time. Let me see if I can simplify this and help you past confusion.
Aracauna - the rumpless, tufted breed that lays blue eggs. Very very rare, you will only find these from breeders.
Ameracauna - these are a bearded and muffed breed with tails and come in standard colors. They will lay a blueish green to green egg. These are a but easier to find than Aracaunas but you will still need to find a breeder.
Easter Eggers - this "breed" is what is sold from hatcheries and feed stores and uneducated people as "Americanas" other mis-spellings, and even often as either of the two true breeds above. It is a cross bred fowl that simply lays a colored egg. I have seen blue, green, red, cream, and other colors from this "breed"
I hope that breakdown helps, I tried to keep it as basic and non-confusing as possible, as this is something many new chicken people get confused about.