Moissanite has similar structure, physical characteristics and higher refractive effect to diamonds, and is known as the most brilliant gem in the world. People in the jewelry industry regard it as the best substitute for diamonds. How to judge the quality of natural moissanite and how to select and identify its quality.
How to judge the quality of natural moissanite
It depends on the cutter. The high-quality moissanite has been carefully cut and processed by the cutter, and each angle has been accurately calculated, so that the moissanite can form the most ideal refraction effect. All the light entering the inner part of the moissanite stone will be refracted together to form a dazzling fire color. The low-quality moissanite, due to inadequate cutting, and part of the angle is too deep or too shallow, will cause light diffusion and cannot be condensed together.
Depending on the color, the color of moissanite has a certain range, from colorless to green, yellow and gray. High quality moissanite is preferred to be colorless. At this time, the moissanite is crystal clear, and the light can be condensed to bloom, forming a colorful fire effect. The low-quality moissanite is not transparent enough, so the light will participate in the variegation, affecting the visual effect.
It depends on the purity, which refers to the number of tiny needle like impurities in the formation of moissanite. The impurities of high quality moissanite are extremely rare and cannot be distinguished by the naked eye, which has no effect on light refraction. The low quality moissanite has more impurities, which affects the refraction of light.
How to select the quality of moissanite
First, conduct thermal conductivity test. If there is reaction, it is diamond or moissanite; No reaction is not both.
Use other instruments: reflectometer, conductivity indicator, C3 testing machine and other instruments to determine whether it is diamond or mullite. Reflectometer: when the test sample is placed on the reflectometer platform, the reflective amount of the test stone will be converted to a numerical value. The values of the reflectometer, diamond and moissanite made in China are 85 ～ 96 and 100 ～ 118 respectively.
Conductivity meter: moissanite is a conductor, while diamonds are mostly insulators. Only a small amount of Type IIb natural blue diamonds and synthetic diamonds are conductors. Place the sample on the metal support, hold the conductivity meter, gently press the probe on the surface of the test stone. If it is mullite, the instrument will light yellow and red and give a warning; If it is a diamond, the conductivity meter will not respond. If the identification sample is inlaid jewelry, the wire clip should be clamped on the metal part. If the probe contacts metal, it will also conduct electricity, causing a false reaction, so the user must pay attention. The diamond ground with poor buoyancy and color inclusions may cause the conductivity meter to react, so additional tests should be considered to ensure accuracy.
C3 testing machine: mainly used to identify diamonds. Put the test stone close to the probe. If it is a diamond, the tester will make a sound. If it is not a diamond, there will be no response. According to the above points, the synthetic silicon carbide can be identified.