The oysters are nucleated with a bead composed of mother-of-pearl and a small piece of mantle tissue. This bead becomes the nucleus of the pearl and is the reason akoya pearls are more often perfectly round.
Carbon definition, Chemistry. a widely distributed element that forms organic compounds in combination with hydrogen, oxygen, etc., and that occurs in a pure state as diamond and graphite, and in an impure state as charcoal.
The element carbon is a non-metallic material that contains six electrons. Charcoal, a form of carbon, has been used since prehistoric times. The name carbon comes from the Latin word carbo which means charcoal.