How Do Oysters Make Pearls?

but it's much more rare. Most pearls are produced by oysters in either fresh water or salt water environments. But to understand how pearls are formed and oysters, you must first understand and oyster's basic anatomy. Okay. An oyster is a bivalve, which means that its shell is made of two halves, which are called valves. The shells valves are

held together by an elastic ligament. The ligament is positioned where the valves come together and usually keeps the valves open so that the oyster can eat, but they can be shut by a powerful abductor muscle inside the shell if you've ever eaten an oyster or other bivalve. This is the tough cylinder of tissue stuck to the inside of the shell. Inside the shell, the oyster also has a body consisting of its heart, gills, and digestive and

reproductive organs, plus its mantle. The mantle is a thin layer of tissue that lines the inner part of the oyster's shell. This organ has glands that extract minerals from water and convert them to the building blocks of the oyster's hard shell. Because as the oyster grows in size, its shell must also grow. The mantles cretes the mineral calcium carbonate, along with a type of protein that together

form the shell. A calcium carbonate is the same material used to make chalk, eggs, shells, and our own bones, and it makes up ninety eight percent of the shell. It coats the underlying protein structure to form the shell's hard surface, a sort of like pouring concrete over steel beams to create a structure that's stronger than either material alone. The oyster shell has different layers. The outermost layer is

a hard outer wrapping called the periostracum. The middle layer is a set of structural struts, called the prismatic layer. The innermost layer is the nacreous layer, also known as the pearl layer or just mother of pearl. It's iridescent and is sometimes used to make buttons or other ornamental items. It also helps form pearls. The formation of a natural pearl inside an oyster begins when a foreign substance slips into the oyster between the mantle and its shell, which

irritates the mantle. It's kind of like the oyster getting a splinter. The oyster's natural reaction is to cover up the irtint by encapsulating the interloper, thereby protecting itself. The mantle covers the irritint with layers of that same nacre substance that's part of the shell, and these concentric layers of nacre will eventually form a pearl. Some oyster species are able to secrete three or four layers of nacre

a day, but each layer will be incredibly thin. Most naked layers that make up a pearl will be as thin as a thousandth of a millimeter that's one thirtieth of an inch or one micron. It'll typically take an oyster at least twenty four months to make a natural pearl that's about five millimeters or one fifth of an inch in diameter, which is about the height of twenty stacked playing cards. It's commonly believed that pearls are formed when a grain of sand enters an oyster. However, this

has recently been disputed as a myth. While it is technically possible for a grain of sand to be at the center of a pearl, the oyster species that produce pearls are found on both sandy oceans and muddy freshwater floors, and they have the ability to expel sand and other small objects like little pieces of seashells. The majority of natural pearls are formed in oysters as response to a

parasitic intruder. A parasitic organisms like drill worms will burrow through the hard shell of an oyster and trigger its mantle to secreate a barrier around the biological interloper. Either way, the resulting pearl is a foreign substance covered with layers of maker. The average natural pearl is about seven millimeters or a quarter inch in diameter. Pearls that grow to a size of ten millimeters or two fifthsphn inch or more are rare and expensive. In general, the larger a

natural pearl, the more valuable it's considered to be. Natural pearls come in a variety of colors, including white, black, gray, red, blue, and green. Most pearls can be found all over the world, but black pearls are indigenous to the Sepsi. A pearls can be uneven in shape. In jewelry, these are called baroque pearls. This happens when the nacre layers encounter resistance during formation, often because the pearl is lodged in muscle

tissue within the oyster. Natural pearls that are pretty much perfectly round are more often used in jewelry and are considered more valuable. Meanwhile, cultured pearls are created by the same process as natural pearls, but require intervention by pearl harvesters. To create a cultured pearl, the harvester opens the oyster shell and cuts a small slit in the mantle tissue. A small ear tints are then inserted under the mantle

and the nakere tissue begins forming a pearl. Some cultured pearls are created using a sort of grafting process in which a pearl nucleus is inserted into an oyster, providing the seed for the growth of a new pearl, and in some cases, simply cutting the mantle is enough to induce the nacre secretion that produces a pearl, and an

irritant doesn't have to be inserted. In general, cultured pearls are far less expensive than natural ones because they can be produced in mass to better meet demand, but both kinds of pearls are still real pearls gems created by animals. Today's episode is based on the article how do Oysters make Pearls? On how Stuffworks dot Com written by Lori L. Dove. The brain Stuff is production of iHeartRadio in partnership with how Stuffworks dot Com and is produced by Tyler Klang.

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