How to distinguish bright pearls from dyed pearls and natural pearls

If you want to buy expensive black pearls, the above identification methods are not assured. Consider taking them to a jewelry appraisal unit for an exact identification: ultraviolet fluorescence test-under ultraviolet radiation, black pearls often fluoresce, ranging in color from bright red to coffee red, but most dyed pearls do not respond to ultraviolet rays or show dim green fluorescence. X-ray detection-X-ray film, the dyed pearls treated with silver salt can show that there is a circle of pale white between the pearl layer and the pearl core of the dyed pearl, which proves its dyeing composition. X-ray fluorescence detection-pearls will emit radiation with a specific wavelength under X-ray irradiation, and the chemical composition and the existence of silver salts can be detected by measuring the wavelength with a spectral measuring instrument. Infrared photography test-shooting pearls with infrared film. The image of the black pearl is light blue. The image of dyed pearls treated with silver salt is yellow, or blue-green to yellow-green. None of the above methods will damage pearls. At the same time, we do not recommend using destructive testing methods such as scraping powder or wiping with dilute acid. Still an old saying goes: find a professional pearl dealer with good reputation, who has knowledge and integrity and disdains to cheat you with credibility. Distinguishing dyed pearls is easier said than done. The following common sense is up to you. You should know there is a close relationship. Color-Black pearls have different shades of light gray to black, and its beauty lies in the color matching on the appearance tone. Turn the black pearl slowly, and you can see the slight rainbow-like flash changing constantly. No two pearls are exactly the same. If you see a string (or even several strings) of black pearls with uniform and dull colors and rich halos, it is almost certain to be dyed pearls. Dyed pearls and black are gathered in the borehole, and the defects are deep. This is easy to observe under a magnifying glass of ten times. Shape-whether the black pearls you see are particularly round, and the thin round black pearls are extremely rare and of high value. Typical black pearls are oblate, pear-shaped, oval and irregular, and many of them have flaws or rings, so the "super-value black pearls" you see are smooth and very "round". Probably dyed. Size-The diameter of seawater pearls in China or Japan is usually less than 9mm, while the diameter of black pearls is at least 8mm, so round black pearls smaller than 8mm are mostly dyed pearls. Price-Are the black pearls you see surprisingly cheap? An 8mm round black pearl costs more than 1000 yuan, while a dyed pearl of the same size only costs 1200 yuan. If you are lucky enough to buy a black pearl at a reasonable price, Jinji requires the merchant to indicate on the receipt that the color of the pearl is natural.