Pearl or parasite enters a bivalve mollusk and settles inside the shell. The mollusk, irritated by the intruder, forms a pearl sac of external mantle tissue cells and secretes the calcium carbonate and conchiolin to cover the irritant. This secretion process is repeated many times, thus producing a pearl. Natural pearls come in many shapes, with perfectly round ones being comparatively rare. Typically, the build-up of a natural pearl consists of a brown central zone formed by columnar calcium carbonate (usually calcite, sometimes columnar aragonite) and a yellowish to white outer zone consisting of nacre (tabular aragonite). In a pearl cross-section
The Pearl of Love and colder" "sense of colour", and, wearying "altogether of carvings and pictures and inlaid ornamentation", has them "put aside". The prince comes "to care . . . more and more" for "a great aisle" that permits "a vista" of, "the snowy wildernesses of the great mountain, the lord of all mountains, two hundred miles away." All who look upon the Pearl of Love are "exalted", yet the prince feels that, "The Pearl of Love had still something for him to do . . . before his task was done." He realizes that the problem is "a certain disproportion about the