How is the pearl earring a symbol that allows the reader to gain insight into the changes and life journey of Griet? What does is represent/symbolize?

According to the author, the pearl earring "is important as a symbol because it represents the world Griet gets drawn into and ultimately rejected from."  Her father's blindness leads to her family's poverty which then leads to Griet's exposure to a whole other world. Griet is cast into the Vermeer household where she must endure jealousy and suspicion. When Griet is allowed into Vermeer's studio, a place even his wife cannot enter, she struggles with the moral values with which she's been raised. This is a world that is totally foreign to her, but it's also one that she's drawn to because she's allowed to participate in Vermeer's artistic creations. Both she and Vermeer know it will be disastrous for her to pose for him, but Griet does it anyway. I think she realizes this will be her only opportunity to be a part of something she knows is special. The earrings belong to Vermeer's wife, and they represent the wealth and prestige of the Vermeer family, but they also represent Griet's purity.

I have posted the link to the interview with Chevalier below.