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, also known as tetrachloromethane (CAS # 56-23-5), is a clear, colorless, non-flammable, halogenated, organic liquid with a distinctive odor. It is sometimes called carbon tet in lab slang. The chemical formula is CCl4 and two equivalent representations of the molecular structure are shown below.