A natural pearl is a concretion formed by a mollusk; it consists of the same material as the mollusk’s shell. Globular concretions both from sea and in fresh water create the pearl as a response to the irritation of grains of sands or parasites.
Pearl is thought to be the finest stabilizer of the emotions. It increases tolerance and flexibility, brings relaxation where there has been tension and frustration. Swedenborg wrote that pearls were truth, celestial and spiritual knowledge, faith and charity.
The pearl was the emblem of purity, innocence and peace. It was sacred to the moon and Diana. In ancient times it was worn by young girls and virgins on whom the protection of "Chaste Diana" was invoked.