Ancient History
Turquoise appeared in Egypt before the 1st dynasty of the Pharaohs, according to the recent excavations. We can meet the mentions of Turquoise in the Egyptian hieroglyphs. They regarded this stone as a mascot. Numerous of the cliffs surrounded the mines covered with the inscriptions containing this word. This term also appears in the papyruses.
Aristotle and Theophrastus also knew this stone. However, Dioscorides doubted that both authors meant Turquoise in their treatises. He supposes that they referred to Lapis-Lazuli. The Arabian writers of the 13th century confirm this fact, as they describe Turquoise as a variety of Lapis-Lazuli.
Pliny in his Natural History tells us about "Callais." There were lots of doubt on the subject. However, the subsequent studies confirmed that most likely Pliny called "Callais" some variety of Turquoise of the green color. We also may meet this word in the Tibet treatise dated the 9th century. Later this gem appears in the Arabic sources of the 10th century, in the works of a traveler named Al-Biruni.
However, the most reliable source where we meet the mentions of Tourquise is Nozhat Namah Ellaiy, a manuscript dated the 11th century (translated just in 1304). Albertus Magnus, nonetheless, also was aware of this gem. But it's worth noting that he lived earlier (1193 -- 1280). Marco Pople describes the place where he first faced with the specimen of this gem. It was the Province of Kerman in Persia and Caindu in China.
Medieval History
The first development of the Chinese Turquoise deposits started in 1366. The work began in Nishapur, Kerman, and Siang-Yang, the provinces of China. In the Arabian world, Turquoise came in vogue in the period between 1300 and 1400. Many Arabian women wore jewelry made of this stone as personal adornment. In that time, Turquoise was inferior just in comparison with Emerald. In Hindu sources, we met the first mentions of Turquoise just in 1502.
Finally, the discovery of America put the beginning of the interest to this gemstone among the European writers. Aztecs called this gem "Chalchihuitl." Several Aztecs' masks containing Turquoise came in Europe. Subsequently, the stone became popular in the Western world. As a result, all the specimens of Turquoise were split into two types, Oriental and Occidental. Later followed the discovery of the organic origin of this semi-precious stone. Turquoise, in fact, it the bones and teeth of some animals covered with copper.
Value
Oriental Turquoise is more valuable compared to Occidental, as these specimens are presumably of the organic origin. However, the debates on the subject lasted during the entire 19th century. The discussions ended with the conclusion that there are two main types of this stone, "Bone Turquoise" and "True Turquoise." As a result, the appearance of Odontolite.
The most valuable specimens come from Meshed, the second populated city in Iran. Next in rank is Oriental Turquoise obtained from Tibet. All other specimens are inferior in their quality and color. The most valuable color possesses a sky-blue tint. Unfortunately, the stones of green color are widespread, whence their low price.