Yes, a green/blue egg is certainly an Araucana egg. They were popularized in Berkeley by e.g. Cafe Fanny (now-closed part of Chez Panisse diaspora), and they fetch the best price in New York City's Union Square farmers market. Mostly, for the novelty. Many factors make big differences in yolk quality, but shell color (or breed, for that matter) isn't so significant. More relevant, do the chickens get to eat bugs? The best chicken coop setup keeps moving the coop across a grass field also used by grazing animals, as described e.g. by Michael Pollan.
Araucana chickens aren't that popular in home coops, because they don't have the greatest temperament, and they're flyers: Unless you clip their wings, no fence will hold them.
There are chickens that lay deep chocolate brown eggs, a far rarer sight. I'd look for those if I were raising chickens. Instead, I take care of neighbor coops.