The Different Dragon Design between Han Dynasty and Qing Dynasty Jade Seals

In ancient Chinese culture,  dragons always were the symbols of royal family especially for the emperors. However, the dragon designs are different for different periods. Thus the style of dragon may serve as an identification element. For example:

The Han Dynasty Jade Seals usually have five dragons with full body.

The Qing Dynasty Jade Seals have dual dragon heads facing opposite direction.