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
Pearl barley Pearl barley Pearl barley, or pearled barley, is barley that has been processed to remove its hull and bran. All barley must have its fibrous outer hull removed before it can be eaten; pearl barley is then polished to remove the bran layer. It is the most common form of barley for human consumption because it cooks faster and is less chewy than other, less-processed forms of the grain such as "hulled barley" (or "barley groats", also known as "pot barley" and "Scotch barley". Fine barley flour is prepared from milled pearl barley. Pearl barley is similar to wheat in