What does Thorin wear to distinguish himself from the others?

Thorin wears a sky-blue hood with a long silver tassel to distinguish himself from the others.

At your service!" said Bifur, Bofur, and Bombur standing in a row. Then they hung up two yellow hoods and a pale green one; and also a sky-blue one with a long silver tassel. This last belonged to Thorin, an enormously important dwarf, in fact no other than the great Thorin Oakenshield himself, who was not at all pleased at falling flat on Bilbo's mat with Bifur, Bofur, and Bombur on top of him.