Were ranked by the ancients among the most precious substances, Revelation 17:4, and were highly valued as ornaments for women. Their modest splendor still charms the Orientals, and a string of pearls is a favorite decoration of eastern monarchs. The kingdom of heaven is compared to a goodly pearl, so superior to all others that the pearl merchant sold all others that he could obtain for it the highest price, Matthew 13:45,46. The gates of heaven are described as consisting of pearls; "every several gate was one pearl," Revelation 21:21. The Savior forbade his apostles to cast their pearls before swine, Matthew 7:6; that is, to expose the precious truths of the gospel unnecessarily to those who reject them with scorn and violence.
Pearls are a stony concretion in a species of oyster, found in the Persian gulf, on the coast of Ceylon, Java, Sumatra, etc., and in smaller quantities in various other places in both hemispheres. It is not known whether the pearl is a natural deposit, or the consequence of disease, or of the lodging of some foreign body, as a grain of sand, within the shells. The pearl oyster grows in clusters, on rocks in deep water; and is brought up by trained divers, only during a few weeks of calm weather in spring. The shell itself yields the well- known "mother of pearl."