Its origin may have evolved on the basis of Arabic "Zarkun", which originally meant "cinnabar and Athena Chu"; Another way of saying it is that it comes from the old Persian word "Zargun", which means "golden yellow". The first official use of "zircon" was in 1783 to describe green zircon crystals from Sri Lanka. Zircon is mainly composed of zirconium silicate, and its chemical molecular formula is Zr[SiO4]. Besides zirconium, it also contains hafnium, rare earth elements, niobium, tantalum and thorium. Zircons are divided into high-type zircon and low-type zircon according to their genesis. In gemmology, zircon can be divided into three types: high type, medium type and low type according to the influence degree of radioactive elements in zircon on refractive index, hardness and density. Zircon belongs to tetragonal system. The crystal morphology is a short columnar crystal composed of a square column and a square bipyramid, and the aggregate is granular. Pure colorless, impurities are red, yellow, blue, purple, brown and so on. The best colors are colorless and transparent red and blue. It has diamond luster, transparent to translucent, and white stripes. The refractive index of "high type" is 1.925- 1.984, and that of "low type" is1.780-1.815. The birefringence "high type" is 0.059 and the birefringence "low type" is 0.005. The "high type" has a large deviation of 0.04. The hardness is "high" 7-7.5 and "low" 6. The density is "high" 4.6-4.8 g/cm3 and "low" 3.9-4. 1 g/cm3. It is very brittle. Under ultraviolet irradiation, "high-type" zircon shows red fluorescence. According to the color, high-type zircon can be further divided into colorless, blue, red, brown, yellow, green zircon and so on. Zircon is often used as a substitute for diamonds because of its strong luster, high dispersibility and high hardness. Has become a leader in low-grade gems. The difference between zircon and similar gems. Zircon is easily mixed with diamond, sphene and artificial rutile. The difference between the two is that diamond is isotropic, dark and hard in polarizer; The birefringence and dispersion of sphene and synthetic rutile are higher than those of zircon, and "fire color" often appears. Evaluation and selection of zircon. The main factors are color, cleanliness, cutting style and weight. The most popular colors of zircon are colorless and blue, and blue is more valuable. Colorless zircon: It is the highest quality variety among gem-grade zircon. Because of its high dispersion and transparency, it is often used as a substitute for diamonds. Blue zircon: It is a high-quality variety with the highest value among zircons, and it is loved by people for its bright blue, flawless transparency and high dispersion. Zircon is brittle and its hardness is much lower than that of diamond, so you must be careful when wearing it as an ornament. In the eyes of westerners, wearing red zircon can play a hypnotic role, drive away the plague and defeat evil. Nowadays, some countries regard zircon and turquoise as "birthstones in December", symbolizing success and victory. High-type zircon is a mineral crystallized in the early stage of magma, which contains no or a small amount of radioactive elements and is harmless to human body. The world's most famous blue zircon, weighing 208 carats, is now in the new york Museum of Natural History. Gem-grade zircon is mostly found in metamorphic rocks and basalts. Gemstone zircon is mainly produced in Sri Lanka, Myanmar, Cambodia, Australia and other countries. South China, North China and East China of China also have output. Artificial gem makes jewelry go out of the expensive world, and Fang Shi Ying zircon is the leader of artificial jade. The scientific name of square zircon is cubic zirconia. It was first synthesized by scientists in the former Soviet Union in 1970s. Its physical and chemical properties are similar to diamonds, and its appearance is more similar, so it is also called "Soviet diamonds". As soon as Shi Ying zircon came out, it was used in jewelry production by literature. According to legend, a large number of fake diamonds were exported to earn foreign exchange, which was discovered many years later. The original cubic zircon was white, and it was not until the 1980s that colored cubic zircon appeared. After a kind of pink cubic zircon named "pink ice" was introduced to consumers through TV shopping malls, there was a craze for buying cubic zircon jewelry in the United States. In 1990s, cubic zircon jewelry became the trend of international jewelry consumption because of its rich colors and low price. The density of Shi Ying zircon is higher than that of diamond, and its refractive index is easy to distinguish from diamond. At present, it is rarely sold as a diamond in the market. In addition, Shi Ying zircon is different from zircon. Zircon is a natural intermediate gem, and its price is much higher than that of Shi Ying zircon. Swarovski Austria is the largest supplier of square zircon in the world, and its precise cutting and fine grinding technology make its square zircon occupy a dominant position in the world. Zirconium drill