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
Palatinate Pearl Palatinate Pearl The Palatinate Pearl is a pearl, kept with, but distinct from the Crown Jewels of Bavaria. The pearl is unique insofar as it is one of only very few part black, part white pearls to occur naturally. The pearl is set between two diamond encrusted snakes, protruding from a bed of leaves, flanked by two flowers. While the exact origins of the pearl are unknown it first appears among the royal Crown Jewels of Bavaria, who were the ruling family of the Palatinate, which gaves its name to the pearl (and possibly its origin). Having traveled with its