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
Pearl, Mississippi franchise by the City of Pearl for cable television to be installed was granted on July 6, 1976. The Pearl Chamber of Commerce was formed on August 24, 1978. On October 1, 1997, Luke Woodham went on a shooting spree that ended at Pearl High School, killing two and injuring seven, after earlier stabbing his mother to death. Over the years the city has redeveloped the former Pearl High School into City Hall, including the Pearl Police Department, public works departments, and city courts. A large auditorium-style Community Center was built next door. Its clock tower is inscribed with the