What did Thorin offer in exchange for the Arkenstone in The Hobbit by J. R. R. Tolkien?
In The Hobbit by J. R. R. Tolkien, the Arkenstone was a beautifully crafted gem that appeared to shine with an inner light. It was greatly prized by Thorin Oakenshield, the leader of the dwarfs, because it was the family heirloom of the descendants of Durin, lost to them when Smaug conquered the Lonely Mountain.
When Bilbo realizes that Thorin, consumed by greed, is unwilling to share the wealth of Smaug with the townspeople who not only suffered greatly from Smaug's anger but also actually defeated him, Bilbo gives the Arkenstone to King Thranduil and Bard to force Thorin to act justly and share the horde with them.
Thorin offers one fourteenth of all the other gold and silver and gems of Smaug's horde in exchange for the Arkenstone.