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.
Carbon tetrachloride (Carbon tet) is a non-flammable colorless liquid with a heavy, sweet odor. Before 1970, carbon tet was widely used as a cleaning fluid in home and industry. Until 1986, the chemical was used as a grain fumigant. Carbon tet is still used to manufacture propellants and other industrial chemicals. In homes, carbon tet may be found in containers of spot remover or in fire extinguishers made before 1970. Carbon tet evaporates quickly and is heavier than water. If carbon tet is spilled in lakes or streams, most of it sinks. If spilled on soil, most of the chemical will evaporate and the vapors will gather near the ground surface. Information on this page has been organized into three categories.