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
City of Pearl and Aras, as she struggles to lead a mission whose goal she doesn't yet consciously know. "City of Pearl" is the name humans have given to a Wess'har city located on planet Wess'ej. Josh Garrod's predecessor, Benjamin, who was taken to see the city by Aras, was said to have wept at its beauty. Many of the people of Constantine relate it to heaven, despite Aras' insistence that the City of Pearl is "just a city." On Planet Earth, Superintendent Shan Frankland (A hardened, self-sufficient, and brutally honest female cop) is preparing for retirement when she is confronted by politician