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.
At room temperatures (20-25 o C), carbon dioxide is an odourless, colourless gas, which is faintly acidic and non-flammable. Carbon dioxide is a molecule with the molecular formula CO 2. The linear molecule consists of a carbon atom that is doubly bonded to two oxygen atoms, O=C=O. Although carbon dioxide mainly consists in the gaseous form, it also has a solid and a liquid form.