I think that the chess piece in "The Count of Monte Cristo" was a powerful symbol. At first it was set up as a mutual keepsake that represented the friendship between Fernand and Edmund. Then after the betrayal of Fernand, he gives the piece back to Edmund to "remember better days." At the end of the movie, after Fernand's life has been taken away to sate Edmund's lust for revenge, Fernand looks into chests he expects to be filled with gold and instead finds only the chess piece. This is very powerful, not only has Edmund revealed his identity this way, he has also renounced their friendship. In addition, by putting it in the chests that were filled with the gold that Fernand thought he had successfully stolen, he illustrates symbolically his disappointment with Fernand for selling out their friendship (the chess piece) for empty material wealth (the chests).