Cultured pearl is calcium carbonate and a fibrous protein called conchiolin. As the nacre builds up in layers of minute aragonite tablets, it fills the growing pearl sac and eventually forms a pearl. Natural pearls are formed by nature, more or less by chance. On the other hand, cultured pearls are human creations formed by inserting a tissue graft from a donor oyster, upon which a pearl sac forms, and the inner side precipitates calcium carbonate, in the form of nacre or "mother-of-pearl". The most popular and effective method for creating cultured pearls are made from the shells of freshwater river mussels
Hymn of the Pearl Hymn of the Pearl The Hymn of the Pearl (also Hymn of the Soul, Hymn of the Robe of Glory or Hymn of Judas Thomas the Apostle) is a passage of the apocryphal "Acts of Thomas". In that work, originally written in Syriac, the Apostle Thomas sings the hymn while praying for himself and fellow prisoners. Some scholars believe the hymn antedates the Acts, as it only appears in one Syriac manuscript and one Greek manuscript of the Acts of Thomas. The author of the Hymn is unknown, though there is a belief that it was composed by the Syriac