Closely examine the passage of Madame Forestier's house when Mathilde discovers and borrows the necklace. What symbolic elements are being used here by the author? Explain.

Suddenly she discovered, in a black satin case, a superb diamond necklace; her heart began to beat covetously. Her hands trembled as she lifted it. She fastened it round her neck, upon her high dress, and remained in ecstasy at sight of herself.

In the above quote, the black box signifies something special, and the diamond necklace represents wealth and beauty to Mathilde. In context, the quote also serves as a symbol of Mathilde's vanity and supports the theme that appearance can be deceiving.... as the diamond necklace she so covets we later learn is merely paste.