Explain the symbolism of Lillian's taking Dagny's diamond bracelet in exchange for the Rearden Metal chain.

Dagny and Lillian see the Rearden Metal chain from opposing points of view. To Lillian it is an ugly, cheap joke Hank had played on her. To Dagny, it represents the best qualities of a high work ethic and intelligence of accomplishment. The exchange also shows that Dagny places greater importance on achievement than she does on mere money.