Closely examine the passage at Madame Forestier’s house when Mathilde discovers and borrows the necklace. What symbolic elements are being used...

First, examine Mathilde's initial response when she sees all the jewelry presented by Madame Forestier--"Haven't you anything else?"  Even faced with all of these riches, it is not good enough for Mathilde--she wants the best of the best.  Next, examine where she finds the necklace that she wants--it is in a black satin case, hidden from view.  It kind of summarizes Mathilde's life; the one thing that she wants is not readily available, and when she sees the unattainable object, she wants it.  Mathilde wants a luxurious lifestyle, but she cannot have it due to her financial situation.  Mathilde wants this necklace, but she cannot have it right away since she has to open the case first.  The very fact that the necklace is hidden away from view gives Mathilde the idea that it is very valuable, and by the end of the story the reader learns that it was not.