As one of the important member among the gem family, turquoise is of wide usage in jewelry making industry, this article is about to introduce the gem from aspects of its chemical property, formation and origins.
The main origin of turquoise is Egypt and Iran. The stone was named turquoise due to the reason that turkey was the necessary land to ship this kind of precious stone to Europe from its origin ancient Persia (which is today’s Iran). As a member that is of the best quality in the turquoise group, Phyruza has the connotation of victory, which can explain the phenomenon why turquoise was inlaid as decoration to weapons such as dagger, sword etc. in ancient time. Gem: TurquoiseRefractive index: 1.610- 1.650Specific Gravity: 2.76Hardness: 5- 6Crystal system: triclinicChemical elements: Cu Al6 [PO4]4 (OH)8 * 4H2OTurquoise is the completely opaque aggregated gem. Color of the stone with the best quality is sky blue, no green and yellow, surely there is no distribution of the dark brown as well. However, the element sky blue alone cannot satisfy conditions of the best quality in that the stone is low temperature hydrothermal product with soft structure frequently, color of some individuals would be faded when they are exposed to sunlight for a long time. The gem-level turquoise can only be found in nodular deposits.The common turquoise in the commercial market is the one covered with spider silk-like veins which was formed due to reason that the struck solution of the stone within the rock cannot be released until the moment when crystallization was being formed after the temperature cool off, the solution would follow to fill in cracks in the rock to form special veins during its formation progress. However, turquoise of the kind is usually not taken as material of vintage jewelry; it is commonly seen to be sold as ordinary jewelry made with silver.With chemical formula as Cu Al6 [PO4]4 (OH)8*4H2O, definition of the stone in gemology is that it is a hydrous phosphate mineral containing copper and aluminum. The replacement of the aluminum element with iron would generate the color of green, chromium and vanadium would deepen the green; zinc is the cause of yellow. Someone might have the doubt, if the stone appearing as green is not blue anymore, can it still be turquoise? This is a good question, for different degree of color among blue and green are formed due to different purity which would have different market as well.Due to the soft structure and porous, treatment of perfusion is the common method used to improve the soft property of its structure, materials of perfusion frequently is resin. Dyeing process is widely applied to change the color of the stone, acid-base materials should be avoided to touch turquoise treated with the two methods above. In 1970, synthesis turquoise was created, which bring one more choice as well as challenge for consumers.For thousands of years, blue sky turquoise of good quality had been produced from ancient Persia constantly, thus “Persian Turquoise” was especially used to refer to the specific area. Not until the early twentieth century, qualified mineral deposits of the stone were found in the west and southeast areas in America, did “Persian Turquoise” become the proper nouns of endemic species of the stone.Several important countries in the world that produce the gem is Iran, the United States, Mexico, China, Chile, Australia etc.. The nishapur deposit in Iran has been the long-term vintage turquoise source. Colorado, California and Arizona produce the gem as well, other two important origins is New Mexico and Nevada. Stone of the kind produced in Yun GAi temple, Yun county, Hubei Province, China is known as the “oriental emerald” is popular among the public as well.
The author is interested in everything related with fields of jewelry and fashion right now, she works hard to let herself have a better understanding of the industries by writing articles, providing pearl beads, Pandora style beads and lobster claws and sharing ideas with people around.