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
Bruce Pearl November 20, 2010, the SEC ordered Pearl to sit out Tennessee's first eight SEC games. After finding out about additional NCAA violations, as well as a violation of the school's substance abuse policy by a player, Tennessee fired Pearl on March 21, 2011—three days after the Vols' blowout loss to Michigan. On August 23, 2011, Pearl was given a three-year show-cause penalty for lying to the NCAA, effective until August 23, 2014. This meant that the sanctions imposed on Pearl would remain in force if he was hired by an NCAA member school within that period. Specifically, he was prohibited