Pearls are so popular that there are more fakes on the market.
For example, processing low-grade goods into high-grade pearls and copying plastic beads into natural pearls not only swindles consumers' money, but also makes the jewelry market smoky.
Pearls are bright and beautiful, and at the same time, they can moisturize the skin and have natural beauty effects.
But fake pearls are just an ornament, which has no value at all. Some "poisonous pearls" are harmful to human body! One of the most notorious is dyed pearls.
Natural precious pearls
pear
Dyed pearls are common fake pearls in the market at present.
In order to make a profit, profiteers process and dye pearls with bad color and pretend to be pearls with good color. This method of counterfeiting is common in precious black pearls and gold beads. Because the cost of counterfeiting is low, it attracts many greedy businessmen.
Do you know that dyed pearls are poisonous?
Dyed pearls are a cancer in the jewelry industry. Dyed products range from several hundred yuan to tens of thousands of yuan, and friends at all levels of consumption may come into contact with them.
Horribly, these dyed pearls are "toxic". They are all bleached with hydrogen peroxide and treated with chemical dyes, which contain a lot of carcinogens and seriously threaten our life and health.
Dyeing pearls is a physical dyeing method, which permeates the surface of pearls to achieve the purpose of dyeing. At present, there are three main dyeing methods, namely water dyeing, oil dyeing and alcohol dyeing.
1, water staining method
This method is the most common. The main components of the dye solution are nitrate, dilute ammonia water, etc. Pearls are put into the solution and dyed at about 40℃. Depending on the dye concentration, the dyeing time varies from a few minutes to more than ten hours.
The pearl dyed by this dyeing method is difficult to penetrate into the pearl, so harmful chemicals will adhere to the surface of the pearl and it is difficult to wash off. When the dye concentration is high, even the orifice will be dyed, which is really toxic everywhere!
2, oil dyeing method
Oil dyeing is to use oily dyes to dissolve in vegetable oil, mineral oil or their mixture, soak pearls in them, open them for a long time, and put them in a high temperature environment before they can be gradually colored.
The color of the pearls dyed by oil dyeing method is not bright, and then the oil attached to the pearls is cleaned with benzene, gasoline and neutral detergent.
3, alcohol staining method
Alcohol dyeing method is to use mixed solution of alcohol and water, polyethylene glycol or other mixed solution with water as dyeing solvent, dye at 40 ~ 60℃, and then soak in alcohol for about one hour after dyeing.
At present, the most common dyed pearls on the market are Nanyang Pearl and Tahiti Black Pearl. Generally speaking, Nanyang pearls are dyed a little more, because Tahiti black pearls have high failure rate and higher cost.
Because the dyed pearls are more and more realistic, many friends don't know how to tell the true from the false. The most direct way is to send them to professional quality inspection institutions. If it is dyed, it will be indicated on the certificate that it is dyed.
But the reality will be more complicated, and sometimes it is too late to send it for testing. Without equipment, how can you identify it with the naked eye?
Teach you four tricks to identify dyed pearls
1, look at the color
The density of nacre is different. When dyeing, pigment precipitation will appear in the relatively low density place, forming color spots, which can be seen on the surface of dyed pearls.
In addition, the color of dyed pearls looks rigid and dull, without the natural aura of natural pearls.
Ps: There is a clear dividing line between stains and other places. If you can't see clearly, you can put the pearl under the strong light of incandescent lamp, and there is nowhere to hide the stain.
Step 2 look at the fluorescence
Dyed black pearls will show dark red fluorescence under fluorescent light, but natural black pearls do not have this characteristic.
Step 3 look at the size
Colored pearls are generally larger, such as Tahiti black pearls. Beads are mostly concentrated between 9mm and 10mm, and those above 1 1mm are considered treasures.
The diameter of Nanyang Golden Beads is also between 9~ 12mm, while Akoya pearls with a diameter over 9mm are rare.
According to the actual situation, if the comparison between size and price seems strange, you should pay more attention.
4. Look at these powders
Rub two pearls and observe the falling pearl powder. The powder of natural pearls is white. If it is dyed pearls, such as dyed black pearls, the powder is black or brown.
This detection method is destructive to some extent, so it should be used with caution when necessary, and it is best to choose pearl ornaments with identification certificates.