Introduction to the structure and morphology of zircon

 
Zircon is a silicate mineral, which can be divided into two types: high type and low type according to its physical properties and chemical composition. Completely crystallized crystals are mostly "high"; those with extremely poor or no crystals are "low". Due to the radioactive elements, the internal structure of zircon is damaged. According to the internal structure characteristics, it is divided into three types: high-type zircon, medium-type zircon and low-type zircon. But in terms of gem value, high-type zircon is more valuable. Zircon is a gemstone with a refractive index that is second only to that of diamond and has a very high dispersion value among natural gemstones. Colorless and transparent zircon is similar to diamond and is a good substitute for diamond. Commonly used zircons are colorless, reddish-brown, maroon, and green. But the most popular colors are blue and colorless. Among them, blue is of higher value, and it is generally changed by optimized heat treatment. Many zircons on the market are sold after being heat treated. Zircon is often heat-treated to improve its quality, or to change its color or type. Because it does not add any other substances in the optimization process, it is still recognized as a natural gemstone in jewelry identification. After optimization, zircon will become more beautiful and easier to sell.
 
The crystals of zircon belong to tetragonal system, a0 = 0.662nm, c0 = 0.602nm; Z = 4. In the structure, Zr and Si are arranged along the c axis to form a tetrahedral unit cell. The crystal structure can be considered as a combination of [SiO4] tetrahedron and [ZrO8] triangular dodecahedron. [ZrO8] Triangular dodecahedrons are closely connected in a co-edge manner in the b-axis direction.
 
Zircon is a gem with special properties. It has a high refractive index and strong dispersion. Colorless or light blue varieties have a strong fire phenomenon like diamonds after processing. Because it is similar in appearance to diamonds, it is known as a gem comparable to diamonds.