WEBVTT - How Do Oysters Make Pearls?

0:00:01.840 --> 0:00:07.320
<v Speaker 1>Welcome to brain Stuff, a production of iHeartRadio Hey brain

0:00:07.320 --> 0:00:11.960
<v Speaker 1>Stuff Laurin vogel bomb here. Most jewelry is fashioned out

0:00:12.000 --> 0:00:15.400
<v Speaker 1>of precious metals and jewels that are made by physical

0:00:15.440 --> 0:00:19.320
<v Speaker 1>and chemical processes in the Earth, but pearls are made

0:00:19.440 --> 0:00:24.320
<v Speaker 1>inside of living creatures oysters. Pearls are the result of

0:00:24.360 --> 0:00:28.280
<v Speaker 1>a biological process and oyster's way of protecting itself from

0:00:28.360 --> 0:00:33.360
<v Speaker 1>foreign substances. Oysters are not the only type of mollusc

0:00:33.440 --> 0:00:37.080
<v Speaker 1>that can produce pearls. Clams and muscles can also produce them,

0:00:37.280 --> 0:00:40.680
<v Speaker 1>but it's much more rare. Most pearls are produced by

0:00:40.680 --> 0:00:44.720
<v Speaker 1>oysters in either fresh water or salt water environments. But

0:00:44.880 --> 0:00:47.959
<v Speaker 1>to understand how pearls are formed and oysters, you must

0:00:48.040 --> 0:00:52.640
<v Speaker 1>first understand and oyster's basic anatomy. Okay. An oyster is

0:00:52.680 --> 0:00:55.160
<v Speaker 1>a bivalve, which means that its shell is made of

0:00:55.200 --> 0:00:59.080
<v Speaker 1>two halves, which are called valves. The shells valves are

0:00:59.120 --> 0:01:02.920
<v Speaker 1>held together by an elastic ligament. The ligament is positioned

0:01:02.920 --> 0:01:06.200
<v Speaker 1>where the valves come together and usually keeps the valves

0:01:06.240 --> 0:01:08.840
<v Speaker 1>open so that the oyster can eat, but they can

0:01:08.920 --> 0:01:12.240
<v Speaker 1>be shut by a powerful abductor muscle inside the shell

0:01:12.840 --> 0:01:16.320
<v Speaker 1>if you've ever eaten an oyster or other bivalve. This

0:01:16.360 --> 0:01:19.720
<v Speaker 1>is the tough cylinder of tissue stuck to the inside

0:01:19.720 --> 0:01:24.200
<v Speaker 1>of the shell. Inside the shell, the oyster also has

0:01:24.280 --> 0:01:27.640
<v Speaker 1>a body consisting of its heart, gills, and digestive and

0:01:27.680 --> 0:01:32.280
<v Speaker 1>reproductive organs, plus its mantle. The mantle is a thin

0:01:32.400 --> 0:01:35.160
<v Speaker 1>layer of tissue that lines the inner part of the

0:01:35.160 --> 0:01:39.600
<v Speaker 1>oyster's shell. This organ has glands that extract minerals from

0:01:39.680 --> 0:01:41.959
<v Speaker 1>water and convert them to the building blocks of the

0:01:41.959 --> 0:01:45.640
<v Speaker 1>oyster's hard shell. Because as the oyster grows in size,

0:01:45.720 --> 0:01:50.720
<v Speaker 1>its shell must also grow. The mantles cretes the mineral

0:01:50.800 --> 0:01:54.680
<v Speaker 1>calcium carbonate, along with a type of protein that together

0:01:54.960 --> 0:01:58.520
<v Speaker 1>form the shell. A calcium carbonate is the same material

0:01:58.680 --> 0:02:01.680
<v Speaker 1>used to make chalk, eggs, shells, and our own bones,

0:02:01.960 --> 0:02:04.200
<v Speaker 1>and it makes up ninety eight percent of the shell.

0:02:04.720 --> 0:02:08.760
<v Speaker 1>It coats the underlying protein structure to form the shell's

0:02:08.760 --> 0:02:12.160
<v Speaker 1>hard surface, a sort of like pouring concrete over steel

0:02:12.200 --> 0:02:17.600
<v Speaker 1>beams to create a structure that's stronger than either material alone.

0:02:18.160 --> 0:02:21.640
<v Speaker 1>The oyster shell has different layers. The outermost layer is

0:02:21.680 --> 0:02:25.640
<v Speaker 1>a hard outer wrapping called the periostracum. The middle layer

0:02:25.760 --> 0:02:29.160
<v Speaker 1>is a set of structural struts, called the prismatic layer.

0:02:30.080 --> 0:02:33.400
<v Speaker 1>The innermost layer is the nacreous layer, also known as

0:02:33.440 --> 0:02:37.320
<v Speaker 1>the pearl layer or just mother of pearl. It's iridescent

0:02:37.400 --> 0:02:40.919
<v Speaker 1>and is sometimes used to make buttons or other ornamental items.

0:02:41.480 --> 0:02:46.400
<v Speaker 1>It also helps form pearls. The formation of a natural

0:02:46.440 --> 0:02:49.960
<v Speaker 1>pearl inside an oyster begins when a foreign substance slips

0:02:50.000 --> 0:02:52.960
<v Speaker 1>into the oyster between the mantle and its shell, which

0:02:53.000 --> 0:02:55.960
<v Speaker 1>irritates the mantle. It's kind of like the oyster getting

0:02:55.960 --> 0:02:59.800
<v Speaker 1>a splinter. The oyster's natural reaction is to cover up

0:02:59.840 --> 0:03:05.120
<v Speaker 1>the irtint by encapsulating the interloper, thereby protecting itself. The

0:03:05.160 --> 0:03:08.359
<v Speaker 1>mantle covers the irritint with layers of that same nacre

0:03:08.480 --> 0:03:12.160
<v Speaker 1>substance that's part of the shell, and these concentric layers

0:03:12.160 --> 0:03:16.880
<v Speaker 1>of nacre will eventually form a pearl. Some oyster species

0:03:16.880 --> 0:03:19.360
<v Speaker 1>are able to secrete three or four layers of nacre

0:03:19.400 --> 0:03:23.560
<v Speaker 1>a day, but each layer will be incredibly thin. Most

0:03:23.639 --> 0:03:26.000
<v Speaker 1>naked layers that make up a pearl will be as

0:03:26.040 --> 0:03:28.960
<v Speaker 1>thin as a thousandth of a millimeter that's one thirtieth

0:03:28.960 --> 0:03:32.560
<v Speaker 1>of an inch or one micron. It'll typically take an

0:03:32.600 --> 0:03:35.320
<v Speaker 1>oyster at least twenty four months to make a natural

0:03:35.320 --> 0:03:37.960
<v Speaker 1>pearl that's about five millimeters or one fifth of an

0:03:38.000 --> 0:03:40.640
<v Speaker 1>inch in diameter, which is about the height of twenty

0:03:40.640 --> 0:03:45.920
<v Speaker 1>stacked playing cards. It's commonly believed that pearls are formed

0:03:45.960 --> 0:03:49.000
<v Speaker 1>when a grain of sand enters an oyster. However, this

0:03:49.040 --> 0:03:52.320
<v Speaker 1>has recently been disputed as a myth. While it is

0:03:52.400 --> 0:03:54.920
<v Speaker 1>technically possible for a grain of sand to be at

0:03:54.960 --> 0:03:57.920
<v Speaker 1>the center of a pearl, the oyster species that produce

0:03:57.960 --> 0:04:02.040
<v Speaker 1>pearls are found on both sandy oceans and muddy freshwater floors,

0:04:02.560 --> 0:04:05.440
<v Speaker 1>and they have the ability to expel sand and other

0:04:05.520 --> 0:04:10.520
<v Speaker 1>small objects like little pieces of seashells. The majority of

0:04:10.600 --> 0:04:13.640
<v Speaker 1>natural pearls are formed in oysters as response to a

0:04:13.680 --> 0:04:18.520
<v Speaker 1>parasitic intruder. A parasitic organisms like drill worms will burrow

0:04:18.560 --> 0:04:20.560
<v Speaker 1>through the hard shell of an oyster and trigger its

0:04:20.600 --> 0:04:25.279
<v Speaker 1>mantle to secreate a barrier around the biological interloper. Either way,

0:04:25.400 --> 0:04:28.920
<v Speaker 1>the resulting pearl is a foreign substance covered with layers

0:04:28.960 --> 0:04:34.719
<v Speaker 1>of maker. The average natural pearl is about seven millimeters

0:04:34.880 --> 0:04:37.640
<v Speaker 1>or a quarter inch in diameter. Pearls that grow to

0:04:37.680 --> 0:04:40.359
<v Speaker 1>a size of ten millimeters or two fifthsphn inch or

0:04:40.400 --> 0:04:44.240
<v Speaker 1>more are rare and expensive. In general, the larger a

0:04:44.320 --> 0:04:48.880
<v Speaker 1>natural pearl, the more valuable it's considered to be. Natural

0:04:48.960 --> 0:04:54.040
<v Speaker 1>pearls come in a variety of colors, including white, black, gray, red, blue,

0:04:54.120 --> 0:04:57.680
<v Speaker 1>and green. Most pearls can be found all over the world,

0:04:57.839 --> 0:05:01.840
<v Speaker 1>but black pearls are indigenous to the Sepsi. A pearls

0:05:01.839 --> 0:05:04.520
<v Speaker 1>can be uneven in shape. In jewelry, these are called

0:05:04.560 --> 0:05:08.640
<v Speaker 1>baroque pearls. This happens when the nacre layers encounter resistance

0:05:08.720 --> 0:05:12.159
<v Speaker 1>during formation, often because the pearl is lodged in muscle

0:05:12.200 --> 0:05:16.040
<v Speaker 1>tissue within the oyster. Natural pearls that are pretty much

0:05:16.080 --> 0:05:19.120
<v Speaker 1>perfectly round are more often used in jewelry and are

0:05:19.120 --> 0:05:24.839
<v Speaker 1>considered more valuable. Meanwhile, cultured pearls are created by the

0:05:24.920 --> 0:05:29.600
<v Speaker 1>same process as natural pearls, but require intervention by pearl harvesters.

0:05:30.400 --> 0:05:33.320
<v Speaker 1>To create a cultured pearl, the harvester opens the oyster

0:05:33.440 --> 0:05:36.120
<v Speaker 1>shell and cuts a small slit in the mantle tissue.

0:05:36.560 --> 0:05:39.160
<v Speaker 1>A small ear tints are then inserted under the mantle

0:05:39.320 --> 0:05:43.400
<v Speaker 1>and the nakere tissue begins forming a pearl. Some cultured

0:05:43.400 --> 0:05:46.520
<v Speaker 1>pearls are created using a sort of grafting process in

0:05:46.560 --> 0:05:49.679
<v Speaker 1>which a pearl nucleus is inserted into an oyster, providing

0:05:49.680 --> 0:05:52.680
<v Speaker 1>the seed for the growth of a new pearl, and

0:05:52.880 --> 0:05:55.680
<v Speaker 1>in some cases, simply cutting the mantle is enough to

0:05:55.720 --> 0:05:58.800
<v Speaker 1>induce the nacre secretion that produces a pearl, and an

0:05:58.880 --> 0:06:04.200
<v Speaker 1>irritant doesn't have to be inserted. In general, cultured pearls

0:06:04.240 --> 0:06:07.000
<v Speaker 1>are far less expensive than natural ones because they can

0:06:07.040 --> 0:06:10.680
<v Speaker 1>be produced in mass to better meet demand, but both

0:06:10.800 --> 0:06:19.520
<v Speaker 1>kinds of pearls are still real pearls gems created by animals.

0:06:20.360 --> 0:06:22.920
<v Speaker 1>Today's episode is based on the article how do Oysters

0:06:22.960 --> 0:06:26.000
<v Speaker 1>make Pearls? On how Stuffworks dot Com written by Lori L. Dove.

0:06:26.520 --> 0:06:29.080
<v Speaker 1>The brain Stuff is production of iHeartRadio in partnership with

0:06:29.080 --> 0:06:31.440
<v Speaker 1>how Stuffworks dot Com and is produced by Tyler Klang.

0:06:31.960 --> 0:06:35.240
<v Speaker 1>Before more podcasts my heart Radio, visit the iHeartRadio app,

0:06:35.360 --> 0:06:38.200
<v Speaker 1>Apple Podcasts, or wherever you listen to your favorite shows,