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 of the Orient Tower Pearl of the Orient Tower The Pearl of the Orient Tower, previously known as Embassy Pointe Tower, is a residential skyscraper located in Manila, Philippines, owned by the Philippine Estates Corporation. Standing at , it is one of the tallest buildings in the City of Manila. The building has 42 floors above ground, wherein 6 floors are for parking spaces, 5 floors for office and commercial purposes, 30 floors for luxury residential units, and 2 floors for penthouse units. There are also 4 basement levels for parking. The Pearl of the Orient Tower was designed by American architectural firm Nadel