Do Clams Make Pearls?

Do Clams Make Pearls?

Do Clams Make Pearls?

The ability to produce pearls is possessed by all mollusks, including oysters, mussels, and clams. Still, only a few freshwater and saltwater mussels are used to produce cultivated pearls of gem quality.

How are pearls made?


Since ancient times, we have worn jewelry made of pearls and decorated with them since they are considered beautiful goods. But how are they made, and where do they come from? In the past, we lacked the ingredients and techniques to create “imitation pearls,” which can now be made from materials like glass or coral. The term “natural pearls” refers to the fact that pearls had to be naturally gathered to be used. Even now, these natural pearls are still being gathered.

Certain varieties of bi-valve mollusks, like clams or oysters, can produce natural pearls. A hinge connects the two halves of a bivalve mollusk’s hard calcium carbonate outer shell. This robust shell serves as protection for its fragile body against predators. These organisms frequently bury themselves on the ocean floor to add a layer of safety. So, this is how an oyster might defend itself against predators like starfish or crabs on the exterior, but how can it defend against infection on the inside?

Similar to how a bacterial infection might enter our systems, a parasite can occasionally enter the shell of a mollusk. The parasite can enter the mollusk while eating or breathing, but in humans, snot in the nose and saliva in the mouth frequently prevent this. The mollusk’s immune system will become active if the parasite can thrive inside its shell. The mollusk will become irritated and develop an immune reaction. This immune reaction results from creating a “pearl sac” surrounding the microscopic invader. Cells from the mantle tissue make up this pearl sac. The mantle is a soft tissue layer between the oyster’s body and its tough outer shell. Then, this pearl sac is covered with conchiolin and chemicals known as calcium carbonate (CACO3). These substances harden, encasing the parasite. The iridescent shimmer in pearls is created when these compounds harden. 

A pearl is created when the chemicals are released and allowed to solidify repeatedly. This can be compared to creating paper mache. Many layers of paper and glue are applied, and the construction is given time to cure to strengthen it. When a mollusk creates a pearl, an identical procedure takes place.

Similar immunological responses are known as granulomas in the human body. The body creates a barrier against a severe illness that it cannot eradicate using a kind of white blood cell known as a macrophage. If this occurs, the granuloma might need to be removed surgically or chemically. A human granuloma may occasionally become harder due to calcification. The bundle of white blood cells will harden and turn white. Unfortunately, unlike the mollusks, our immune reaction isn’t quite as attractive.

What is a clam pearl?Do Clams Make Pearls?

A general term used to describe diamonds discovered inside specific bivalves found worldwide is “clam pearl.” The most sought-after among collectors are clam pearls, which come in a variety of hues and designs. Although they are typically smaller than saltwater pearls found in oysters, they can grow fairly enormous. Clam pearls often lack the great brilliance of farmed pearls and are not perfectly spherical.


Clam pearls, also known as river pearls, are typically made by freshwater bivalve mussels that inhabit rivers and streams. Native Americans were among the first to regularly consume the soft-bodied mollusk known as the mussel as food. Native Americans gathered clam pearls as priceless jewelry that they traded and wore.


A calcium carbonate-like material is thinly coated on clam pearls. The mussel secretes this material to cover an outside irritant that gets into the shell while feeding. Clams have two hinged shells that may open and close to get food, but occasionally a parasite or other foreign object slips through and irritates the mussel’s sensitive body. The calcium carbonate secretions transform into a pearl over time.


Due to their flawless roundness and brilliance, cultured pearls are usually more expensive than clam pearls. Although there may be other hues of clam pearls, white is the most typical. Other colors include pink, lavender, and a collectible blue clam pearl. The species of mussel that creates clam pearls determines its color.


Quahog clam pearls come in various purple hues and are produced by littleneck clams that may be found along the United States’ east coast. Due to their unusual colors, these irregular saltwater pearls immediately gained popularity. In addition, they might be prized for their erratic shapes, which set them apart significantly from more expensive cultured pearls.


Where such a clam pearl is located inside the shell determines its shape. The bivalve tends to become more rounded as some form on the lip. On the back of the shell, others may form in the form of wings. Most clam pearls are affixed to the heel of a shell, which explains why they have erratic shapes. A flawless clam pearl is quite uncommon.


In the earlier, clam shells were gathered and utilized to make pearl buttons. The United States of Iowa near the Mississippi River once had more than 40 button producers. The shells were shaped into circles by factory employees, who then cleaned and ground them with pumice stones and water. The finished item has holes bored into it to manufacture buttons for the textile industry.

Clams Vs. Oysters

  • Aside from edible and non-edible species, clams and oysters often come in two different varieties. For example, clams come in hard-shelled and soft-shelled varieties, whereas oysters come in true and pearl.
  • Clams and oysters can be found in some of the same places. Both can survive in either freshwater or saltwater. Oysters, however, are more frequently discovered in saltwater.
  • Clams are higher in vitamin C, manganese, selenium, and iron than oysters, which are higher in zinc, potassium, and phosphorus.


As a natural defense against an irritant like a parasite entering their shell or harm to their delicate body, freshwater and saltwater mussels produce pearls.

The aragonite and conchiolin layers that make up the oyster or mussel’s shell are gradually secreted by them. This results in a nacre called mother-of-pearl, which encases the irritant and shields the mollusk from it.


Can a pearl be found in a clam?

Certain varieties of bi-valve molluscs, like clams or oysters, can produce natural pearls.

How rare is a pearl in a clam?

The International Gem Society states that they are “exceptionally uncommon,” occuring in only one out of every 5,000 shells.

How long does it take for a clam to make a pearl?

A pearl can be created in a process that lasts anywhere from six months to several years. Even before this, the mollusk must reach a mature age in order to make a pearl, which takes around 3 years. When a mollusk reaches this mature age, it can only start the pearl-making process naturally or with human assistance.