Turquoise
Hardness 5-6 specific gravity 2.4-2.9
Refractive index 1.62
Wear: avoid contact with cosmetics and high temperature sun
Turquoise is one of the oldest gemstones. Because it contains "copper" and "iron", it presents the unique color of sky blue to green. Turquoise is the birthstone of December.
Turquoise is a copper mineral with a chemical composition of "hydrous copper aluminum phosphate" and a Mohs hardness of 5 to 6. It is an opaque polycrystalline gem suitable for grinding and polishing as an arc with a waxy to "porcelain" luster.
Turquoise, the English name of turquoise, originated from the French word "TURQUOIS" in the 17th century, which means "Turkish". The reason is that turquoise first entered Europe from the mining area of Khorasan Province in Persia via Turkey, and its Chinese name will also be translated as "Turkish stone".
The history of human understanding Turquoise
Turquoise is valued in many ancient cultures because of its soft sky blue color: the rulers of ancient Egypt, Aztecs, Persia, Mesopotamia, the Indus River Basin, and the Chinese Shang Dynasty have used Turquoise as decoration.
Turquoise was used in ancient Egypt from the first dynasty or earlier. The most famous turquoise jewelry in Egypt came from the tomb of Tutankhamun, turquoise inlaid on the mask of Pharaoh.
People of ancient Persian Empire put Turquoise in sky blue on their necks or wrists to resist unnatural death. If the color of the stone changes, people will think that death is near.
The Aztecs will inlay Turquoise in sacrificial supplies; the Apache tribe will use Turquoise as a talisman, believing that the gem can improve the archer's hit rate.
According to exodus 28 turquoise is used for the breastplate of the high priest of Judaism.
The color and characteristics of turquoise
The ideal turquoise color is between "dark sky blue" and "Robin eggshell". The lighter the color, the lower the value. Turquoise is colored by "copper" and "iron". Turquoise with more copper is bluer, while Turquoise with more iron is greener.
Turquoise is a porous, polycrystalline gem, often variegated or dark brown to black vein texture
Origin of turquoise
Turquoise is one of the earliest gemstones to be mined. Many Turquoise deposits in history have been exhausted. Because the mining area is small and remote, it is mainly small-scale seasonal mining. Most are mined by hand. Turquoise is also often a byproduct of large-scale copper mining, especially in the United States.
Iran has always been an important source of turquoise, producing the highest quality natural turquoise. The ore belt is limited to the neshabur mining area (near Mashhad, the capital of Khorasan, Iran, on the Ali mersai peak, 2012).
Turquoise produced in Egypt comes from Sinai, which is more green and transparent.
Turquoise is produced in the southwest of the United States, such as Nevada, Arizona and California, with more abundant colors, from blue to green. Turquoise in the United States usually has high porosity and is easy to be crushed, so it needs to be cemented with resin.
Optimization of turquoise
Turquoise can be processed to improve color and durability (such as increasing hardness and reducing porosity), such as oiling, waxing and resin stabilization.
Reconstitution Turquoise
This is the most extreme treatment. Turquoise, too small to be used alone, is ground into powder and bonded into blocks with resin. Turquoise sold in the name of "reconstituted Turquoise" is usually artificial turquoise, almost free of natural turquoise, completely made of resin and dye. Powdered turquoise is also called block turquoise.
Factors affecting value
The value of turquoise is mainly determined by the color and "texture". The closer the color is to sky blue, the higher the value is, and the closer the texture is to porcelain.
Any form of optimization will affect the value of gemstones, and try to avoid buying Turquoise after optimization.
Wearing and preservation of turquoise
Perfume, cosmetics, sweat and most jewelry cleaners will damage turquoise, while wearing cosmetics, sunscreen or hair gel, they should not wear Turquoise ornaments.
Turquoise will dehydrate and change color when exposed to heat, so avoid high temperature and long-term sunlight exposure. Do not wear turquoise on the beach or in the sun.
After wearing, wipe the surface with a soft cloth and store separately to avoid scratching with jewelry with high hardness.
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