In Act 5, Scene 5, Cymbeline asks Iachimo:
“That diamond upon your finger—say,
How came it yours?”
The diamond is mentioned three times in Pericles:
Maisa: “To me he seems like diamond to glass.” (Act II, Sc. 3.)
Helicanus: “Whom if you find, and win unto return,
You shall like diamonds sit about his crown.”
Cerimon: “She is alive: behold
Her eyelids, cases to those heavenly jewels
Which Pericles hath lost,