CVD Synthetic Diamond Gemological Characteristics, Identification And Application

Diamond has the highest hardness, strength and wear resistance of the material nature havebeen found, with other materials can’t match the excellent performance, making it a full range ofmaterials in the best in the world, plays an irreplaceable role in many industry fields. However,natural diamond less reserves, mining difficulties, can’t meet the needs of industry and theconsumption field, and the number and size of synthetic diamond HTHP method is limited, theprocessing cost is high, so many of their applications have been restricted, but chemical vapordeposition (CVD) diamond synthesis technology and perfect could resolve these the currentproblem, CVD method for gem diamond single crystal material prepared has implementedalmost all the characteristics of natural diamond.This paper summarizes the main features of synthetic diamond by measured with a series ofinstruments including not only ordinary instruments but also DiamondSureTM, Near-infraredspectrometer, Raman spectrometer, DiamondPlusTM, UV-Vis spectrometer, DiamondViewTMandPhotoluminescence spectrometer.1. Rough CVD synthetic diamond has typical serrate layer structure and laser cutting marks.2. Colorless-nearly colorless CVD synthetic diamond samples were classified as type Ⅱa.Although the peaks related to N or H has not been observed in IR absorption spectra, thedefect-related absorptions due to trace nitrogen and silicon elements. They can still be detectedby UV and PL shown as270nm,737nm and360nm absorption peaks in IR and503.5nm,575nm,596nm,597nm,625.6nm,637nm and737nm absorption peaks in PL.3. Fluoroscopic image shown as orange, blue-green or mixed green-blue, none-strongblue-green phosphorescent and has closed textures, layer structure, crystal domain and blendedcolors.4. Mixed treatment about CVD synthetic diamond, especially to identify whether has beenheated, is still the most difficult part. There is a change of intensity in the absorption peak whileusing the different lighting conditions. It still under discussion whether the intensity absorption of503.3nm,625.6nm and596nm,597nm can be used as feature to identify heated treatment.With the increasing of CVD synthetic diamond technology and the decreasing of its’ costgradually, CVD synthetic diamond may become the main jewelry material, replace the naturaldiamond, in the future. Gem lab must work to identify new technology to improve the syntheticmaterial continuously and the latest progress, ensure the orderly and healthy development of thediamond industry.