Zircon, also known as "zircon", is called "hyacinth stone" in Japan and the English name is Zircon. The source may be derived from the Arabic "Zarkun", the original meaning is "Chensha and Yinzhu"; the other said that it is derived from the ancient Persian "Zargun", meaning "golden yellow". The first official use of "Zircon" was in 1783, used to describe green zircon crystals from Sri Lanka.
The main component of zircon is zirconium silicate, and its chemical formula is Zr[SiO4]. In addition to mainly containing zirconium, it also contains lanthanum, rare earth elements, lanthanum, cerium, lanthanum and the like. Zircon is classified into high-type zircon and low-type zircon according to the cause. In gemology, it is divided into three types: "high type", "intermediate type" and "low type" according to the degree of refractive index, hardness and density of radioactive elements in zircon. Zircon is a tetragonal system. The crystal form is a short columnar crystal form consisting of a square prism and a tetragonal double cone, and the aggregate is granular. The pure color is colorless, and the color containing impurities is red, yellow, blue, purple, brown, etc. The best color is colorless and transparent red and blue. With diamond luster, transparent to translucent, streak white. The refractive index is "high" 1.925-1.984, "low" 1.780-1.815. The birefringence "high" is 0.059 and the "low" is 0.005. The "high" dispersion is strong, 0.04. Hardness "high" 7-7.5, "low" 6. Density "high" 4.6-4.8 g / cm3, "low" 3.9-4.1 g / cm3. Strong brittleness. Under high temperature, "high" zircon is red fluorescent.
According to the color, the high-type zircon can be further divided into: colorless, blue, red, brown, yellow, green zircon and the like. Due to its strong luster, high dispersion and high hardness, zircon is often used as a substitute for diamonds. Has become the leader of the middle and low grade gems.
The difference between zircon and similar gemstones. Zircon is easily mixed with diamonds, vermiculite and synthetic rutile. The difference is that the diamond is a homogeneous body, dark in the polarizer, and high in hardness; the birefringence and dispersion of vermiculite and synthetic rutile are higher than that of zircon, and often appear "fire".
Evaluation and purchase of zircon. The main factors are color, clarity, cut style and weight. The most popular colors of zircon are colorless and blue, and the value of blue is higher. Colorless zircon: It is the highest quality variety of gem-quality zircon. Because of its high dispersion, transparent and colorless, it is often used as a substitute for diamonds. Blue zircon: It is a high-quality variety of zircon, the highest value, and is loved by bright blue, transparent and high dispersion. Zircon is brittle and has a much lower hardness than diamonds. Care must be taken when wearing jewelry.
In the eyes of Westerners, wearing red zircon can play a hypnotic role, driving away the plague and defeating evil. Some countries today use zircon and turquoise together as the "December Birthstone", which symbolizes success and wins. High-type zircon is a mineral of early magma crystallization, containing no or less radioactive elements, and is harmless to the human body. The world's most famous blue zircon, weighing 208 carats, is now housed in the Museum of Natural History in New York, USA.
Gem-grade zircon is prolific in metamorphic rocks and basalts. The world's gem-quality zircon is mainly produced in Sri Lanka, Myanmar, Cambodia, Australia and other countries. China's South China, North China, and East China also have output.