File:Peter Pracownik - Knight of Wands (The Hobbit).jpg

According to Thorin’s description, the Arkenstone was “Like a globe with a thousand facets, it shone like silver in the firelight, like water in the sun, like snow under the stars, like rain upon the moon.”

Bilbo discovers it in the treasure hoard and secretly takes it for himself, even then sensing that his agreed-upon share was not intended to include this special gem. After the besiegement by the Men of Laketown and the Elven King, whilst on night duty with Bombur, he

slips on his Ring and goes over the wall, making his way to the besiegers’ encampment. There, meeting with Bard and the Elven King he reveals the Arkenstone to aid them in their bargaining with Thorin. He was fully aware of Thorin’s willingness to starve himself to death rather than surrender any of the Dragon’s treasure!