A diamond is hard and rough to the touch.

Ben’s final mantra of “The jungle is dark, but full of diamonds” in Act II turns Willy’s suicide into a moral struggle and a matter of commerce. His final act, according to Ben, is “not like an appointment at all” but like a “diamond . . . rough and hard to the touch.” As opposed to the fruitless, emotionally ruinous meetings that Willy has had with Howard Wagner and Charley, his death, Ben suggests, will actually yield something concrete for Willy and his family. Willy latches onto this appealing idea, relieved to be able finally to prove himself a success in business. Additionally, he is certain that with the $20,000 from his life insurance policy, Biff will at last fulfill the expectations that he, Willy, has long held for him. The diamond stands as a tangible reminder of the material success that Willy’s salesman job could not offer him and the missed opportunity of material success with Ben. In selling himself for the metaphorical diamond of $20,000, Willy bears out his earlier assertion to Charley that “after all the highways, and the trains, and the appointments, and the years, you end up worth more dead than alive.”