Lord Rukh

From Srafopedia

When the corpse of this Arctic explorer who died of exposure was discovered, a stone an inscribed in a mysterious language was found in his grasp; this stone is among the displays in the Royal Arctic Institute, Lyra’s favorite stop in London. Mrs. Coulter shows this to her on their first day together.

In our world, a rukh is an enormous bird in Persian mythology mentioned in the Arabian Nights and by Marco Polo.[1]