Persian

Persia, now known as Iran, has been an important source of Turquoise for more than 2,000 years. Turquoise was originally named by Iranians as "pirouzeh", meaning "victory", and later called “firouzeh” after the Arab invasion. In Persian architecture, blue turquoise was used to cover the domes of their palaces because the blue color was a symbol of heaven on earth.
This deposit, which is blue naturally, and turns green when heated due to dehydration, is restricted to a mine-riddled region in Nishapur, the mountain peak of Ali-mersai, which is tens of kilometers from Mashhad, the capital of Khorasan province, Iran.
The majority of Persian Turquoise was imported to the U.S. before sanctions were imposed on Iran by the U.S. Government in the late 1970s.