Green ghost baking color is additive color. According to relevant public information, "Green Ghost" is a kind of sapphire, and the main color is blue or blue-green, while "baking" is a jewelry processing technology, which darkens or brightens the color of gemstones by heating, thus increasing the color saturation and color of gemstones. Therefore, "green ghost baking" refers to a method of adding color to sapphire by heating it to make it brighter or darker. Baking treatment will change the internal structure of sapphire, thus affecting its physical and chemical properties. Therefore, we must carefully choose the processing plant and process to ensure the quality and safety of sapphire.