Vincent reluctantly introduced to Qin Shiou, saying that now that the development of science and technology is getting more and more advanced, and there are more and more means of counterfeiting, it is much more difficult for jewelers to identify black pearls.

At present, there are four main methods of cultivating black pearls: silver salt treatment, radiation radiation, dyeing bead nuclei, and film coating.

The most used is the first one, Vincent called a staff member in a white coat to come over to show Qin Shiou, this method is to put the pearl into several reagents to soak, after soaking for a while, the staff took it out, said: "This is silver nitrate and dilute ammonia solution, which can make the surface of the pearl covered with a layer of silver plating." ”

He then put the silvery-white pearl into an airtight container and illuminated it with a strong light, so that slowly, the color of the black pearl changed from white to black.

"It contains hydrogen sulfide, which can reduce the chemicals in the coating under strong light, turning the silvery-white coating black. Of course, this is just a demonstration, but in fact the steps are more cumbersome, take longer, and make the black pearls more realistic. ”

Qin Shiou gave a thumbs up and said: "The wisdom of human beings is really infinite, and fraud can be so technical, the 21st century is really the era of science, I have to go to university for further study." ”

"Learn how to fake?" Vincent teased.

Qin Shiou smiled, in fact, he was a little weak-hearted, because his black pearls were also a bit fake, and a common way of counterfeiting was pearl nucleus dyeing, which was implanted into the pearl oyster after dyeing the pearl nucleus black, and constantly adding melanin preparations to the pearl oyster during the pearl formation process, and the final pearl was pure black.

He used to grow because pearls were too slow. Small pearls are placed in the black lipped bay, and the black lipped oyster secretes substances that surround them before the black pearls come out.

The experts found by Vincent demonstrated two other methods of counterfeiting to Qin Shiou. One is to irradiate the pearl under gamma rays from a cobalt source to make it black, which is the ray radiation method. The last one is the film coating. A thin layer of black gum is applied to the surface of the pearl......

While Qin Shiou was watching these demonstrations, one hundred and twenty-eight black pearls were assigned to different experts, who began to discern them.

Again, starting with physical discrimination, looking at the colors first, this time using a microscope-like instrument with a bracket that can hold a circle of eight black pearls at a time. Once the Black Pearl is placed on it, the bracket holds it up, and several rays of light scatter on the Black Pearl from all sides.

Vincent explains, "No two leaves in the world are exactly the same. Nor are there two black pearls that are exactly the same. Natural black pearls come in shades ranging from pale gray to black, and their beauty lies in the color on the look. In astigmatism, the black pearl is slowly turned, and a slight sparkle can be seen constantly changing, like a rainbow. ”

Qin Shiou stared at those black pearls carefully, then shook his head awkwardly and said, "It seems that this requires professional vision, I can't see it." ”

Vincent laughed, "Of course, of course you can't see it, because it has to be seen with a ten-fold mirror." ”

This microscope is not just about the color of black pearls. It is also necessary to measure its roundness, diameter, brightness and other parameters.

Vincent said that wild black pearls rarely produce particularly rounded types, and almost all of them have some unusual shapes, such as pear-shaped, drop-shaped, dumbbell-shaped, and so on. The black pearls brought by Qin Shiou here are almost all perfectly round, which is why they are so valuable. One can cost tens of thousands of dollars.

At this point, Vincent teased again, saying that when he first saw the black pearls he offered to make the Night Empress in such a brilliant shape, he subconsciously thought that they were all cultured black pearls. So he didn't come to see Qin Shiou at the beginning, otherwise such a potential customer. He's going to have to be hospitable anyway.

Qin Shiou smiled: "Maybe it's really cultured pearls, because they are all cultivated in my fishing farm." ”

Vincent laughed too. Then he asked in a seemingly casual tone: "With so many high-quality black pearls, I'm afraid that Tahiti's annual output is only like this, Qin, how did you get it?" Don't tell me that your fishing grounds have more black lipped oysters than Tahiti. ”

Not all black lipped oysters can produce black pearls, according to probability statistics, the probability of Tahitian black pearls being produced is 1 in 10,000, that is, only one in 10,000 black lipped oysters can produce black pearls! And the black pearls produced in this way may not be what they are, they may be irregular in shape, or they may be poor in color, so there are very few high-quality black pearls that can be produced every year.

This is also the reason why the price difference is so big, imitation pearls only cost a few dollars, a cultured pearl only costs tens of hundreds of dollars, wild pearls usually cost thousands of dollars, and the price of the best natural pearls is definitely tens of thousands, hundreds of thousands of dollars.

The most important thing in physical testing is the machine test, although the eyes and feelings of treasure experts are very powerful, but people have missed their hands and horses, and there is always the possibility of looking away. Of course, precision machines are not completely reliable, but the eyes of experts and the judgment of precision machines make the final result very reliable.

As a result, Vincent later introduced a series of black pearl identification techniques to Qin Shiou, mainly of which are four, each of which is aimed at the same counterfeiting technology.

The first is the ultraviolet fluorescence test, which is for thin film coating technology. The ultraviolet light is shot out by the light machine on the black pearl, and under the irradiation of ultraviolet light, the black pearl often fluoresces, and the color changes, ranging from bright red to coffee red, which is extremely gorgeous. Thin-film coated pearls have a layer of black gum on the surface, so they do not respond to ultraviolet light.

The second is X-ray detection, Vincent said that this technology is specifically to determine whether cultured pearls have been treated with silver salts, and after the black pearls are X-rayed, the film projected by the machine can distinguish the dyed pearls treated with silver salts, and there is a light white circle between the nacre and the pearl nucleus.

The third method is called X-ray fluorescence testing, which also uses an X-ray machine, but instead of taking pictures, it shoots light. All jade emits radiation at a specific wavelength when exposed to X-rays, and measuring the power of the wavelength with a spectrometer can tell whether it is a pure black pearl or a cultured pearl made of radiation.

The last is the infrared photographic test, which is aimed at cultured pearls made by dyed bead nucleus technology, which is extremely penetrating and can penetrate into the pearl nucleus. In the case of cultured pearls, the angle of infrared light will change when it penetrates the black pearl and then shoots out because of the uneven texture.

This is the one that Qin Shiou is most worried about, because some of the black pearls he has here use other kinds of pearls as pearl cores! (To be continued.) )