Grapefruit is oblate in shape, ranges in diameter from 3 to 5 inches and can weigh up to 150 g. Characteristically, it has thick, tough skin than that in the oranges. Inside, the fruit is segmented into arils as in other citrus fruits.
Nacre (/ËneÉªkÉr/ NAY-kÉr also /ËnÃ¦krÉ/ NAK-rÉ),[1] also known as mother of pearl, is an organic-inorganic composite material produced by some molluscs as an inner shell layer; it also makes up the outer coating of pearls. It is strong, resilient, and iridescent.
Nacre is composed of an organic, horn-like compound called conchiolin, and calcium carbonate (CaCO 3) in the form of the minerals aragonite or calcite. All species of bivalves are capable of producing pearls, but only a few can secrete a nacreous coating that has the attractive pearly luster of gem pearl.