(The). Dioscorides and Pliny mention the belief that pearls are formed by drops of rain falling into the oyster-shells while open; the rain-drops thus received being hardened into pearls by some secretions of the animal.
According to Richardson, the Persians say when drops of spring-rain fall into the pearl-oyster they produce pearls.
Precious the tear as that rain from the sky Which turns into pearls as it falls on the sea.
“Pearls ... are believed to be the result of an abnormal secretory process caused by an irritation of the mollusk consequent on the intrusion into the shell of some foreign body, as a grain of sand, an egg of the mollusk itself, or perhaps some cercarian parasite.” —G. F. King: Gems, etc., chap. xii. p. 211.
Cardan says that pearls are polished by being pecked and played with by doves. (De Revum Varietate, vii. 34.)
For Cleopatra melting her pearl in honour of Antony, see Cleopatra. A similar act of vanity and folly is told by Horace (2 Satire, iii. verse 239). Clodius, son of AEsop the tragedian, drew a pearl from his ear of great value, melted it in a strong acid, and drank to the health of Cecilia Metella. This story is referred to by Valerius Maximus, Macrobius, and Pliny. Horace says,
Qui sanior, ac si Illud idem in rapidum flumen jaceretve cloacam!
Sir Thomas Gresham, it is said, when Queen Elizabeth dined with him at the City banquet, melted a pearl worth 15,000, and drank to her health.
Here fifteen thousand pounds alone clap goes Instead of sugar, Gresham drinks the pearl Unto his queen and mistress.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894