I think Bilbo was the greatest treasure in Thorin’s life, and definitely more important than the Arkenstone. This is proven by his behavior immediately after the showdown on the ramparts. The shock of being betrayed by Bilbo was overwhelming. The closest, the most beloved, the one whom Thorin trusted ABSOLUTELY. Thorin is dressed in armor and armed, but the most important thing is that now he knows exactly where the stone is - it is in Bard’s pocket! If the Arkenstone really was that important to Thorin, he would attack immediately! But Thorin suddenly doesn’t care. From this point on we hear nothing more about the Arkenstone. He goes into the throne room and just sits there, filled with pain and resentment. We must understand that Thorin has a difficult fate and hard life, and Bilbo became a real salvation for his wounded soul. And now he feels that he has lost the only one that was really important to him. And of course it's not a stone.
















