With the increasing pursuit of jewelry, people have to know some jewelry identification skills. Some people say that a piece of green jade was taken by Dow filter. If it turns red, it can be said that this jade is dyed, and if it doesn't change color, it is its true color. This statement is mechanical and parrot-learned. We know that Dow filter is a kind of filter, which only allows red light and orange light to pass through. The fuel used for jadeite dyeing usually contains chromium salt. It will emit red light when its concentration is high, and it will appear red under Dow filter. However, if the dyed color is not deep, the concentration of chromium salt is not high, and it is red under Dow filter, which is not easy to observe. In addition, natural green jadeite sometimes contains a small amount of substances that emit red light. When observing green jadeite with Dow color filter, it needs to be carefully analyzed, which will be indicative and cannot make a conclusive judgment. So what's the difference between natural green and dyed green of jadeite? We already know the reason why jadeite is dyed. The reason why natural jadeite has three colors of green, white and purple is because the particles that make up jadeite have three colors of green, white and purple. Therefore, when we look at the color of a natural jadeite, its color and crystal are inseparable, while the original crystal of dyed jadeite is colorless. The dye that enters jadeite through impregnation permeates along the intergranular cracks or some tiny cracks of the crystal, so there is an obvious boundary between color and crystal. Identification of diamonds: As diamonds are the first noble and luxurious ornaments, it is not uncommon to replace or pass off diamonds with cheap gems, artificial gem or even glass. Common fake diamonds are as follows: ① Zircon: Very similar to diamonds, it is the best substitute for diamonds. The identification method is that zircon has polarization and large birefringence. Observing the processed zircon prism surface with a magnifying glass of 10 times, it can be seen that the bottom edge line has obvious ghost, but the diamond has no ghost phenomenon. (2) Glass: The refractive index of glass is very low, and there is no flickering color light like diamonds; Especially when it sinks into the water, the glass product loses its luster and immediately shows clues. (3) Soviet diamond: cubic zirconia, first developed by the Soviets, hence the name. Soviet diamond is a synthetic compound, but it is very close to natural diamond in dispersion and refractive index, and it also has the attractive appearance of "fire" light. But its hardness is low (8.5), so it can be distinguished from diamonds. Moreover, the thermal conductivity is much lower than that of diamond, so it can be identified and distinguished accurately by "thermal conductivity meter". ④ Crystal: Although crystal is a transparent crystal of natural minerals, it looks like a diamond after processing, but it lacks the colorful light of diamond. Identification of Ruby: Natural ruby is "ten Hong Jiu cracks", and natural ruby without any flaws and cracks is extremely rare. Artificial rubies have the same color, few internal defects or crystal inclusions, and are clean and large. As a precious gem, natural rubies over 3 carats are very rare in the market. If you encounter a big ruby, you should pay attention, because the value of natural ruby is thousands of times higher than that of artificial ruby. A little carelessness will "take medicine." Natural ruby has a strong "dichroism". The so-called dichroism means that there are two colors of red and orange red from different directions. If there is only one color, it may be red spinel, garnet or red glass. Red spinel and natural ruby are very similar, and they are most easily confused, so be very careful. Identification of sapphire: The color of natural sapphire is often uneven, and most of them have a flat growth line. Artificial sapphires are of the same color, and their growth lines are arc-shaped strips, and they are often breadcrumb-shaped or beaded bubbles in the body. Natural sapphire also has obvious dichroism, one direction is blue, and the other direction is blue-green. Other gemstones are different in color from natural sapphires and can be distinguished. In addition, the simplest method can be hardness measurement. Natural sapphires can carve traces on topaz, while other sapphires are difficult to carve traces on topaz. Therefore, when buying jewelry, if there is no instrument around, as long as there is a topaz, sometimes some problems can be solved. Identification of tourmaline: tourmaline is an intermediate gem, but due to its high price, pink and bright blue tourmalines also appear as imitations. There are two common imitations, one is artificial coloring with colorless tourmaline; One is made of red glass. The identification method is that the real tourmaline often has obvious dichroism and can be seen as a ghost; Tubular inclusions or cotton wool can be seen in the body, and the crystal cross section is curved triangle. These characteristics are not possessed by imitations. The tourmaline dyed by workers is not difficult to identify because its color is dull and there is no "treasure light" of natural tourmaline. Identification of crystals: rock crystals are clear and transparent, often containing cloud-like, star-like or flocculent gas-liquid inclusions, and often have microcracks. In addition, the rock crystal is polarized, and you can see the phenomenon of twin crystals, such as a crystal ball. Looking down from the top, there will be a double image. Synthetic crystal or glass products are uniform and pure in the body, without cracks, and often have small bubbles inside. Looking down at the sphere, you can't see the ghost of the line below. Through touch recognition, we can feel that the proportion of synthetic crystals is greater than that of rock crystals; Crystal stone feels cold and glass feels warm. Identification of pearls: pearls can be divided into natural pearls and cultured pearls, and cultured pearls can be divided into seawater pearls and freshwater pearls. Natural pearls are low in output and expensive; Moreover, cultured pearls can be produced in large quantities, so the price is much lower. The main difference between them is that natural pearls and cultured pearls have no nuclei. The inner core of natural pearls is often just some sand or parasites, or even no inner core. However, the inner core of cultured pearls is artificially made large round beads, so the outer coating is thin. On the body surface, natural pearls rarely roll because of their random growth environment and poor roundness. The inner core of cultured pearls is round, so the roundness of pearls is better. Natural pearls are transparent because of their long growth time, delicate texture, thick nacre, smooth skin and few "convex bubbles". The cultured pearls are thin in layer, rough in texture, "waxy" in luster, and have some uneven "bubbles" on the surface, so the transparency is poor. If it is a perforated pearl, observe the hole carefully with a magnifying glass. If it is a cultured pearl, you can generally see a brown boundary inside the pearl, which is the boundary between the inner core and the pearl layer that grows later. At present, imitation pearls often appear in the market, which are generally made of glass beads coated with fish scale powder or silver powder. Their luster is obviously different from that of real pearls, and their weight is also different, so people with a little experience can identify them. If you scrape off a nail or a knife, the true face of Lushan Mountain will be revealed immediately.