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
Parable of the Pearl but loss? Has your trust in yourself and your merits Come to naught before Christ and His cross? </poem> A less common interpretation of the parable is that the merchant represents Jesus, and the pearl represents the Christian Church. This interpretation would give the parable a similar theme to that of the Parable of the Lost Sheep, the Lost Coin, and the Prodigal Son. The phrase "Pearl of Great Price" has also been interpreted more widely to apply to things of great value in a number of religious contexts. For example, it is the title of a selection of Mormon