The Blue Pearl (1920)

When thief Frederick Thurston returns from abroad with a stolen blue pearl, he sells the jewel to Holland Webb, a gigolo living off the funds of his wealthy wife Laura. Holland then presents the pearl to his mistress Sybil Trent, who wears it to a reception hosted by the Webbs. Thurston is also in attendance and is planning to reclaim the pearl. During the course of the party, the lights are extinguished, and when the electricity is restored, Sybil discovers that her gem is missing. When Police Commissioner Richard Drake is called in to solve the crime, Laura, who is aware of her husband's infidelity, confesses to him that she stole the jewel as evidence in a divorce suit against her husband. Laura and Webb are divorced, and she falls in love with Drake.