True Blue? Central WA University Has A Way To Know For Sure If you have lived in Central Washington for any length of time, chances are pretty good that you have at least heard of the Ellensburg Blue Agate and perhaps you even own some Ellensburg Blue Jewelry. And maybe just maybe you've been rocking hunting up by Ellensburg hoping to find a true blue of your own. " the third rarest gemstone found around the world.... started drawing attention around the 1920s and have become more popular throughout the years... Because of its elegance, (the tribal chiefs of the Kittitas Indians) were the only individuals allowed to wear this magnificent gem."