Turquoise grade identification method
One of the most popular ancient jade in turquoise, nowadays, in addition to making various accessories, it is also used in the production of home furnishings. The turquoise has various colors such as light blue, medium blue, green blue and green. Very nice, how to identify turquoise, Xiaobian and everyone to see:
Grade 1 Turquoise: It is a bright sky blue, with pure and uniform color, strong luster, translucent to slightly transparent, and a glassy surface. The texture is dense, delicate, tough, without iron wire or other defects, and the blockiness is large.
Secondary turquoise: dark blue, blue green, emerald green, strong luster, slightly transparent. The texture is tough, the iron wire or other defects are few, and the blockiness is medium.
Three-level turquoise: light blue or blue-white, light yellow-green and other colors, poor gloss, relatively stiff texture, obvious iron wire, or more defects such as white brain, tendons, and heart, and the block size varies.
Natural turquoise identification method:
It is common to use natural waxing, dyeing and injection molding to modify natural turquoise. This is usually accepted by the jewelry industry. After all, there are too few high quality turquoises.
1, dyeing
(1) The color of the dyed turquoise is unnatural. The dyed turquoise on the domestic market is often dark blue green or dark green, and is too uniform, but at the crack, the color becomes darker.
(2) The color of the dyed turquoise is very light, generally around 1mm, and some places may have a light-colored core.
(3) Wipe with a cotton ball dampened with ammonia to stain blue-green.
2, injection molding
Injection molding includes the injection of colorless and colored plastics. Injection-treated turquoise can be identified by:
(1) Refractive index: Injection molding is generally lower than 1.61.
(2) Relative density: The relative density of injection molding is relatively low, generally less than 2.76.
(3) Hardness: Mohs hardness of injection molding, generally 3-4, the injection of turquoise is prone to scratches.
(4) Hot needle test: injection molding will produce a special spicy smell, and there will be burn marks.
(5) Infrared spectroscopy: Strong absorption between 1450 cm and 1500 cm caused by plastic may occur, and in the new injection molding treatment, a strong absorption band of 1725 cm appears.
Turquoise imitation identification method:
1, gibbsite
This is a mineral that is symbiotic with turquoise. The main difference from turquoise is:
(1) Its color is relatively light and it is difficult to reach sky blue;
(2) Glass luster, which is different from turquoise waxy and earthy luster;
(3) Brittleness, easy to collapse, and turquoise is more resilient;
(4) low hardness;
(5) having a muddy smell;
(6) The density is lower than turquoise.
2, blue green glass
The main difference between it and turquoise is its glass luster, shell-like fracture, and bubbles and swirls that may be seen inside.
3. Silicon malachite
This is a mineral that is very similar in appearance to turquoise. The main differences are:
(1) bright colors and high transparency;
(2) the refractive index is low;
(3) The density and hardness are relatively low.
4, recreate turquoise
This is made up of some turquoise particles and blue powder materials that are pressed at a certain temperature and pressure. This material can be identified by the following aspects:
(1) Structure: The appearance is like porcelain, with obvious granular structure;
(2) Acid test: It is blue due to the copper-containing compound, the copper salt can be dissolved in hydrochloric acid, the acid is dripped on the surface, and it is wiped with a white cotton ball, and the turquoise will fade.
Turquoise is one of the most popular jade stones, but now there are very few high-quality turquoises on the market, so you should pay attention to the quality and other issues when you buy.
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