The synthetic blue spinel and blue glass are not only uniform and clean in color, but more importantly, if you look at the gem in the light, you will see the phenomenon that the synthetic spinel emits red light, which will be more clear if you observe it under the Chelsea filter. Sapphire is still gray-blue or blue-green under Chelsea, while spinel and glass (including CO) are red, so they can be distinguished quickly.
In addition, the identification of sapphire should also pay attention to distinguish the blue sapphire changed by diffusion method. Diffusion method, also known as surface bleeding method, is to "diffuse" some chromogenic elements (CI) to the crystal surface by physical methods, thus improving the color of gemstones. Because this method is often only to improve the surface of gems, and its thickness is mostly less than 0.3MM, it is still considered as a deceptive method in the jewelry industry.
Sapphire after diffusion treatment is often pure blue and light blue. If handled properly, it is difficult for the naked eye to recognize. If possible, diiodomethane (an organic heavy liquid, toxic, use with caution) can be added. If it is natural, its color will often fade and the boundary of the gem will be "hidden". If the color is changed by infiltration, the boundary of the gem will be very clear, and it can be seen that the edge of the gem is darker than the middle color, showing a color ring phenomenon. Under the magnifying glass, some blue gems that have changed color after diffusion often have uneven color on their surfaces (for example, the color will deepen in some concave and convex places); If you polish it after bleeding, there will be a dull feeling, and there will often be small pits on the surface.
Regarding the distinction between sapphire sandwich stone and coated stone, the method is similar to that of ruby. Please refer to the previous contents.
The key natural blue gemstones are mostly flat growth lines, ribbon-shaped or crystalline inclusions, which are often bicolor, that is, one direction is blue and the other direction is blue-green. On the surface, it is sapphire crystal glass, which can quickly disperse the fog. Generally, the fog disappears at the moment you leave your mouth at the top of the watch mirror, so you can't see the fog on the surface.
2. Tapping method
Tap the surface gently with your nails (if it is too short, please borrow it from the salesgirl. Remember, it must be light, the fake is likely to be broken. If you want to pay for it, that's bad. If the sound is dull, it is sapphire crystal face. If it is ordinary crystal or glass, the sound will be crisp.
Three. Drip method
If possible, drop a drop of water on the surface and then stand it up. The water drops don't scatter, but slide down slowly. Must be slow, slow, slow. This is a sapphire crystal.