* * Master Feng's blue gold pendant may fade * *. Although the blue burning of pure gold is done on the surface of gold through dozens of processes such as pinching silk, lighting blue and burning blue. , colored by inorganic minerals, fired at a high temperature of more than 800 degrees, will not fade. But it may fade after a long time. In addition, gold tends to turn black when exposed to lead. Cosmetics and hair dyes contain trace amounts of mercury and lead, so try not to wear gold jewelry when dyeing hair. Gold welds often turn black because different manufacturers use different fluxes. Wearing gold ornaments for a long time and touching the body and air for a long time will make gold look dull.