1级黄色录像片,日日夜夜人人精品,99中文字幕在线观看,人人综合,95精品视频,麻豆乱淫一区二区三区,午夜激情成人网



Synthetic diamond: A gem-quality diamond made by artificially simulating the growth environment of natural diamonds. After more than ten years of development, industrial production is becoming more and more mature, and the size of single particles is constantly expanding. In addition to the synthesis of yellow and colorless diamonds, it is also possible to synthesize rare blue and pink diamonds in natural diamonds. Natural diamonds are comparable, even to the full extent of natural diamonds.

The maximum specification of single crystal is 15 carats/grain, and the mass production is 1-3 carats/grain, 3-5 carats/grain, 5--8 carats/grain. More than 5 carats are required for customization.