In the Qin dynasty, sumptuary laws barred anyone but the emperor and empress from using seals carved from jade, which was considered the most precious material. Subsequently, restrictions on the use of jade for making seals persisted. From the Yuan dynasty on, however, jade seals were frequently given to important Tibetan religious and political authorities as gifts from the Chinese emperor (Ou and Qi, 1). Seals of various precious materials were important objects in the diplomatic gift giving rituals between Tibet and China. Chinese emperors would always have dozens of seals carved from precious materials.

Here are some images of seals that were owned by political authorities in Tibet and China:
kk51.jpgsealfifthdalilama-cl.jpga2jadeseal.jpg

From right to left the the images show:
Seal of the Yuan Spiritual Preceptor, Chogyal Pagpa (1235-1280)
http://www.himalayanart.org/image.cfm/101514.html

Seal of the Fifth Dalai Lama (1617-1682)
http://www.himalayanart.org/image.cfm/101502.html

Seal of the Qing dynasty Qianlong emperor (1711-1799)
http://www.gio.gov.tw/taiwan-website/5-gp/museum/kk15.htm