Morenci turquoise is another American classic, highly regarded and sought after by collectors. Though the Morenci turquoise mine produces a wide range of colors from blue to green, the most desirable is a deep blue color with a heavy iron pyrite matrix and occasionally some spider-webbing.
The Morenci turquoise mine is located in Southeastern Arizona. It is the by-product of a large open-pit copper mining operation and dates back to 1864. William “Lucky” Brown was offered the mining rights in the 1950s and the Brown family has worked the mine since. Though no turquoise is actively being produced at the Morenci mine, small amounts do still come to market each year from the stock that was mined previously. [Source]