The main component of 750 gold is gold, the hardness of gold is 2.5, and the hardness of platinum is 4-4.5, so it is usually platinum hard. However, because 750 gold is 75% pure gold and 25% other precious metal elements are added, the hardness of gold is increased, the melting point is reduced and the color is changed, so the stability of 750 gold is very good, and the inlaid diamond is not easy to deform, so the diamond is stronger. Of course, it is not that platinum is not firmly inlaid, but that platinum is of high purity, and the probability of deformation of the ring during wearing is higher than that of 750 gold.