"she named the infant “Pearl,” as being of great price"
A Water Baby (1900) depicts a baby as a pearl
Public DomainA Water Baby (1900) depicts a baby as a pearl - Credit: Herbert James Draper

This is a reference to the Book of Matthew, which asserts that “the kingdom of heaven is like unto a merchant man, seeking goodly pearls: Who, when he had found one pearl of great price, went and sold all that he had, and bought it” (Matthew 13:45-6). Pearl, purchased by Hester’s sexual sin, is also its redemption. She is in this sense a living analogue of the scarlet letter itself, and her symbolic function is just as protean.

The Parable of the Pearl illustrated in a stained glass window
Public DomainThe Parable of the Pearl illustrated in a stained glass window - Credit: StAnselm
Oyster with pearl
GNU Free Documentation LicenseOyster with pearl - Credit: Manfred Heyde