Bilbo Finds the Arkenstone
Bilbo Baggins finds the Arkenstone, the legendary Heart of the Mountain, during his solitary exploration of Smaug's lair after the dragon has departed. This discovery is not merely the acquisition of a treasure; it is the pivotal moment in which Bilbo, acting entirely on his own initiative, seizes the one object that Thorin Oakenshield values above all the gold in the hoard. The act transforms Bilbo from a passive member of the company into a figure who holds the key to the coming siege, and it marks the point at which his burglar's role becomes genuinely consequential, for better and for worse.
The Discovery in the Dark
After the dwarves refuse to follow him into the vast, dark hall, Bilbo takes a small pine-torch lit by Oin and Gloin and crosses the floor alone. He climbs the great mound of treasure, and as he ascends, a white gleam draws him forward. The light grows into a little globe of pallid radiance, and when he stands before it, he sees the Arkenstone shining with its own inner light, cut and fashioned by the dwarves long ago from the heart of the mountain. It takes all light that falls upon it and changes it into ten thousand sparks of white radiance shot with glints of the rainbow. Bilbo's hand is drawn toward it by its enchantment; he lifts the large, heavy gem, shuts his eyes, and puts it in his deepest pocket.
A Burglar's Choice
Bilbo immediately recognizes the gem from Thorin's earlier description and knows that it is beyond price. He thinks to himself, "Now I am a burglar indeed!" but he also feels an uncomfortable premonition that the picking and choosing of his share was never meant to include this marvellous gem, and that trouble will come of it. He decides he must tell the dwarves about it "some time," but for the moment he keeps it hidden, wrapped in an old bundle of tattered oddments that he later uses as a pillow. This secret possession sets him apart from the dwarves, whose dwarvish hearts are rekindled by the mere glimpse of gold, and it places Bilbo in a position of unique power and peril.
The Heart of the Conflict
When the siege of the Mountain begins and Thorin refuses to negotiate with Bard and the Elvenking, Bilbo's plan takes shape. He steals out of the fortress at night, crosses the river, and delivers the Arkenstone to his adversaries. He tells them, "This is the Arkenstone of Thrain, the Heart of the Mountain; and it is also the heart of Thorin. He values it above a river of gold. I give it to you." The Elvenking and Bard are astonished, and the gem becomes the bargaining chip that forces Thorin to parley. When Thorin learns that Bilbo has given away his most prized possession, he erupts in fury, calling Bilbo a "descendant of rats" and threatening to throw him from the wall. The incident nearly destroys their friendship and leads to Thorin's bitter repudiation of Bilbo, though it ultimately paves the way for the final confrontation with the goblins.
Aftermath and Legacy
After the Battle of Five Armies, Thorin lies mortally wounded. On his deathbed, he takes back his harsh words and parts from Bilbo in friendship. Bard lays the Arkenstone upon Thorin's breast as he is buried deep beneath the Mountain, saying, "There let it lie till the Mountain falls! May it bring good fortune to all his folk that dwell here after!" The gem thus returns to the earth from which it was mined, a symbol of the treasure that brought both glory and ruin. For Bilbo, the Arkenstone episode marks the moment when he fully steps into his role as a decisive agent, not merely a lucky hobbit, and it remains a central memory of his adventure, a secret he carries home to Bag-End along with his two small chests of gold and silver.
