It's not fake that gems turn black in the light. Because to judge whether a gem is good or not is to look at it under natural sunlight and artificial light. It looks bright under strong light and turns black under ordinary sunlight, and it will not change if it is a fake made of glass and plastic. So it's not fake that the gem turns black under the light. Jewelry refers to stones or minerals that can meet the requirements of jewelry after grinding and polishing.