In Hamlet, Shakespeare mentions the pearl twice under the name UNION.

King: “The King shall drink to Hamlet’s better breath;

And in the cup an union shall he throw,

Richer than that which four successive kings

In Denmark’s crown have worn.

Hamlet: “Drink of this potion. Is thy union here?

(Act. V, Sc. 2.)

CHAPTER XXXIII
FORMS, COMPOSITIONS, CHARACTERISTICS,
ZODIACAL CLASSIFICATION, AND
PLACES OF ORIGIN

AMBER