The evolution happens to the shapes of head and paw of the dragon.Generally speaking, the motifs of dragon evolve from simple form of earlier period into more detail form of later period. The dragon head of the Han Dynasty jade is different from that of the Qing Dynasty jade. The number of toes in a paw implies whether the jade is belonged to Emperor or not. Three toes for the Tang Dynasty emperor while five toes for the Qing Dynasty emperor.