Here's why she *doesn't* likely possess genuine expertise in jewelry:
* Her Social Status: She's from a lower-middle-class background and dreams of a life of luxury. Someone accustomed to truly high-quality jewelry would likely have more experience with it, either through family wealth or social circles.
* Her Focus on Appearance: Her desire isn't for lasting value or artistry, but rather for the *appearance* of wealth and elegance. She wants to impress others at the ball. This suggests she's more concerned with how something looks than with its actual worth or craftsmanship.
* The Twist Ending: The fact that the necklace turns out to be a cheap imitation reveals her inability to distinguish real from fake. Someone truly knowledgeable about jewelry would likely have noticed clues indicating it wasn't genuine.
Therefore, Mme. Loisel is likely fooled by the *sparkle* and perceived value of the necklace, rather than recognizing genuine quality based on expertise. She's easily impressed by something that looks expensive, reinforcing the story's theme of the dangers of vanity and misplaced priorities.