Seal of the 16th Karmapa
To the left is an impression of one of the Karmapa's seals, signed by the 16th Karmapa,
the hand-writing above the seal translates as
'Karma Kagyu Dharma institution'
A similar seal design to the above, perhaps a copy, clearly shows the letters 'karmapa' carved into the stone seal.
The script style is the father to the Horyig seal script called Phags-pa.
In both seal designs, the Phags-pa letters sit on an open lotus, radiating aura lines, above the letters are three 'jewels' representing the Buddha, Dharma and Sangha, either side of which are the sun and moon.