Au900 is 90% gold. Au900 is made on the basis of au750 gold, which consists of 90% gold and 5% other metals. Its texture is relatively hard, and it also has good ductility of pure gold, and its color is close to gold. Although it has many advantages, it is not common.

AU900 is actually only a symbol of gold purity, and it is actually quite common in jewelry stores. The dragon and phoenix bracelets and buttons in wedding suits are generally made of au900.

Because the texture of gold is soft, this bracelet is made very wide and thin. Therefore, the buttons need to be reinforced, using au900 gold to prevent deformation or damage when wearing. Then, like this bracelet, other locations are generally au999, which is what we call 24k gold. Another place is the gold earrings behind the gold earrings. The general material is also 900, otherwise it will not be buckled.