What happens to their "dwarfish hearts" when thorn and the others see the piles of gold and jewels in Smaug's lair?

They all of a sudden become bold,

"Their mere fleeting glimpses of treasure which they had caught as they went along had rekindled all the fire of their dwarfish hearts; and when the heart of a dwarf, even the most respectable, is wakened by gold and by jewels, he grows suddenly bold..."

That became bald