How is a pearl formed inside the seabed oyster? Which has been the highest-priced pearl?

Pearls are produced when a tiny piece of grit or sand becomes trapped inside the shell of an oyster. This irritates the oyster, which then produces a layer of what is called mother-of-pearl or nacre around the particle to prevent it harming the oys-tear's internal organs. (Mother-of pearl is a hard, iridescent substance produced by the oyster normally to coat the inside of its shell). Layer upon layer of mother-of-pearl is coated around the particle until a pearl is formed as shown in the diagram below. Pearls vary considerably in size and shape and no two pearls are exactly alike. Japanese? Bahraini and Tahitian divers free dive (i.e. without an oxygen canister) to collect the pearl-bearing oysters for which their regions are well known. In the past, thousands of oysters had to be collected to reap a handful of pearls, and for this reason pearls were a very valuable commodity. 

Today, however, the farming of cultured pearls has dispensed with the need for harvesting natural pearls to make cultured pearl, a tiny pellet made from nacre or mussel shell is inserted into an oyster. The oyster then works to protect itself against the pellet and coats it in successive thin layers. Pearls come in various colors, but the most valuable pearls are white and silvery-white salt-water pearls. The highest price of $ 8,64,280 was paid by the buyer of an egg-shaped pearl weighing 15.13 grams. The pearl, formerly part of the French Crown Jewels was sold at Christie's, Geneva, Switzerland on May 21, 1988. •