Susan Miller

·Master of Fine Arts in Jewelry Design, Pratt Institute, 2012

·Bachelor of Arts in Gemology, University of California, Los Angeles, May 2005

·Editor-in-Chief, White Victoria (2018 - present)

·Write and research feature articles and profiles for print and online publication

·Contributing Writer, Modern Jeweler and Ornament

·Write and publish freelance articles for IGS and WSJ Magazine

·Jewelry Appraiser (2012 - 2020)

What is a pearl? This issue has been debated for centuries, and the answer remains a mystery. Though many believe pearls are nothing more than a simple bead, they could not be more wrong. The truth is that pearls are one of the most precious gems in the world. In this post, I will explore the history and science of these gems, the process of their formation, as well as their many uses and applications. I will also explain the different types of pearls and why some are more valuable than others. So, what is a pearl? Let's find out!

What is a pearl?

pearl is a beautiful gemstone produced by a living creature, typically a mollusk. It is an organometal consisting of an aggregate of calcium carbonate and a horny substance, conchiolin.


Pearls are formed when an external irritant, such as sand, gets trapped inside the mollusk's shell. In other words, they are a limestone organic compound resulting from the protective reaction of the mollusk organism to a foreign substance.


Pearls have been used for centuries as both a decoration and a currency. In some cultures, pearls are believed to have special powers and are often worn as talismans. Today, pearls are still popular as both jewelry and as an investment.


The variety of colors and sizes for pearls is almost infinite. These characteristics directly affect their price and value.

What color can pearls be?

A wide range of colors of pearls can come in, such as white, black, pink, and blue. Importantly, pearls can come in more than a hundred shades. The palette depends not only on the types of pearl mollusks but also on the place of their birth, the chemical composition of the water, and the maturity of the pearls. For example, black pearls come from black-lipped oysters that live in greenish-black waters.


Maturity is measured in microns of aragonite plate thickness. The most brilliant and high-quality layers are considered layers with half a micron thickness. These are not freshwater but sea pearls.


The seawater pearl shines more brightly compared to the freshwater abode mate. The reason is that the seawater is saturated with a huge amount of salt, which greatly affects the chemical composition of the mother-of-pearl shell.

What sizes do pearls come in?

Pearls can also be found in a variety of sizes. However, the most valuable ones are typically the largest and have the most intense color. 


Pearls can be small (up to 2.5 mm), medium (2.5–6 mm), and large (over 6 mm). Pearls with a diameter of more than 7–8 mm are of high gem quality. They are rare and highly valued. Sizes of large pearls can be from 10 to 15 millimeters. The London Museum has a pearl weighing 85 g, and its diameter is 45 millimeters.

The largest pearls are found in the Pinctada maxima, an oyster species native to the coasts of Australia, Indonesia, and the Philippines. These oysters can grow to over four feet in length and produce pearls up to 14 inches in diameter.

How does a pearl form?

Pearl is the only precious gem of animal origin: it is not formed in the earth's bowels, like diamonds or emeralds, but in the shells of bivalve mollusks.

A pearl is created when an irritant - typically a piece of sand or other small objects - enters an oyster's shell and lodges in the body tissue. The oyster protects itself from potential irritants by coating it with nacre, pronounced NAY-Ker. This substance is secreted by the oyster's mantle tissue and creates multiple layers around the object. The nacre coats the irritant and eventually forms a lustrous pearl.


Thanks to mother-of-pearl, the mollusk removes the inconvenience caused by a foreign object. The mollusk reduces friction and irritation by immuring it in a smooth carbonate ball.

Thus, in the center of the pearl, there is always a "center of crystallization," the embryo of the pearl. But it also happens that there is no foreign object in the center of the pearl. In this case, a gas bubble, a drop of liquid, or a piece of mollusk tissue can serve as a seed for the formation of a pearl - it gradually decomposes during the formation of a pearl.

How long does a pearl grow?

It is quite hard to answer this question as the process depends on several factors, such as the type of oyster, the water temperature, and the amount of food available. Generally speaking, it takes several months for a pearl to form. However, some pearls can take up to several years to form.


For example, it takes approximately two years to form Akoya pearls and up to four years to form one South Sea pearl. Regarding the latter, it takes two years for a small clam to become an adult and another two years for a pearl to grow.

Tahitian pearls are grown for 16-24 months. Farmers control salinity, water temperature, and other parameters throughout this period. Still, only 40% of oysters produce good-quality pearls.

Natural pearls vs. cultured pearls

Usually, scientists identify two primary types of pearls: natural and cultured. While both types of pearls are beautiful and valuable, there are some key differences between them.

Natural pearls are created by chance when a piece of grit or other foreign object finds its way into an oyster's shell. The oyster then secretes a specific substance called nacre around the irritant, gradually forming a pearl. Because they occur naturally, natural pearls are quite rare and can be very expensive.


Humans create cultured pearls. A small part of the tissue from another oyster is inserted into the host oyster, which then secretes nacre around it. Cultured pearls are much more prevalent than natural ones, and as a result, they tend to be less expensive.


When it comes to appearance, natural pearls are often more irregular in shape than cultured pearls. Besides, they are also smaller in size. Cultured pearls, on the other hand, are typically more uniform in shape and size.


In terms of value, natural pearls are worth more than cultured pearls. However, both types of pearls can be valuable, depending on size, color, and clarity.

Saltwater pearls vs. freshwater pearls

We can distinguish key points in which saltwater and freshwater pearls differ. Most notably, the environment in which they are grown plays a big role in shaping the final product.


Saltwater pearls are grown in oysters that live in oceans or other bodies of salt water. The warm temperatures and high salt content of these waters provide the perfect environment for oysters to thrive. The oysters that produce saltwater pearls are typically much larger than those that produce freshwater pearls, allowing for a greater quantity of pearls to be produced at once.

Freshwater pearls are grown in mussels in rivers, lakes, and ponds. The cooler temperatures and lower salt content of these waters result in a slower growth rate for the mussels, resulting in smaller pearls. However, because freshwater pearls can be cultivated in a broader range of environments, they come in a greater variety of colors and sizes than saltwater pearls.


Interestingly, saltwater pearls are typically rounder and have a more lustrous surface than freshwater pearls. They also tend to be more valuable due in part to their rarity.


Freshwater pearls are more common, and as such, they come in a greater variety of shapes and sizes. They also tend to be less lustrous than saltwater pearls. However, their value can vary widely depending on the quality of the pearl.


Saltwater pearls are generally considered more high-end and luxurious, while freshwater pearls are more affordable.

Saltwater Pearls

We can distinguish different cultured saltwater pearls, including the Akoya, South Sea, and Tahitian.

Akoya Pearls

Akoya pearls are a type of saltwater gem grown in oysters in the Akoya region of Japan. The sizes of mollusks, in the wings of which gems are grown, are insignificant. However, the diameter of up to 7 cm allows specialists to place a maximum of 3 cores for seeding future jewelry. Akoya is harvested in late autumn or early winter. During this period, they are fully formed and acquire the best shine.

South Sea Pearls

South Sea pearls are mined from saltwater oysters in the South Seas region, encompassing Australia, Indonesia, Myanmar, and the Philippines. Such pearls are grown using many very rare mollusks called Pinctada maxima. This species requires pristine, nutrient-rich sea water to live. Pearls can range from 9mm to 20mm, making them the largest of all varieties. From one mollusk, you can usually get only one pearl. However, sometimes you can find two or three at once.

Tahitian pearls

Tahitian pearls are grown in saltwater oysters in the French Polynesian islands. The cultivation process begins with the collection and cultivation of oysters. For a pearl to form, the shell must be ground and rounded. When an oyster reaches 2-3 years of age and 3.5-4 inches in diameter, it is ready to nucleate. The imperfections of Tahitian pearls are due to the sand particles getting inside when the pearl is formed.

Freshwater pearls

Freshwater pearls are grown in freshwater mussels in lakes, rivers, and ponds. These mussels are native to many parts of the world. The growth cycle of a freshwater pearl is similar to that of a saltwater pearl, except that freshwater pearls do not require a grain of sand to initiate the process. Instead, a small piece of tissue is inserted into the mussel, which causes the latter to produce a pearl. 


However, the advantages of the freshwater species are that the mollusk can grow several pearls simultaneously. This is because several nuclei can be planted simultaneously into the mantle (the fold of the animal's body under the shell) in a freshwater mollusk. In contrast, in the saltwater pearl, the implant is implanted only in a single instance in the reproductive organs. This is another reason saltwater beads are much more expensive than their freshwater counterparts.

Origin of pearl jewelry

The history of pearls in jewelry is a long and lustrous one. For centuries, pearls have been associated with royalty and luxury, and many well-known people have worn them. 


One of the earliest examples of pearl jewelry comes from the tomb of Queen Puabi, who ruled over the ancient Sumerian city-state of Ur in the 3rd millennium BCE. Queen Puabi was buried with a stunning array of jewelry, including a pearl necklace and earrings.


Pearls have also been found in the tomb of Egyptian pharaoh Tutankhamun, who ruled from 1332-1323 BCE. Tutankhamun's tomb contained the world's largest collection of pearls, many of which were strung together in necklaces.

Who are the most famous pearls wearers in history?

Queen Elizabeth I of England was the most famous wearer of pearls in the Western world. She was a major supporter of the arts and, in particular, a lover of pearls. During the late 16th and early 17th centuries, her enthusiasm for pearls helped make them quite fashionable in England. Queen Elizabeth is said to have owned over 3000 pearls and would often wear them in elaborate necklaces and earrings.


Other famous historical figures known for their love of pearls include Empress Josephine, the first wife of Napoleon Bonaparte, and American heiress Daisy Fellowes. More recently, Audrey Hepburn and Jackie Kennedy are two style icons often associated with pearls.

These accessories are still seen as a symbol of luxury and status. They are often worn by celebrities on the red carpet and are a popular choice for bridal jewelry.

How to choose pearls?

When it comes to pearls, the white and almost perfectly round gems are the most popular. But there are many different pearls, so how do you know which ones to choose? Here are a few tips:


1. Consider the type of pearl. You may choose between natural or cultured pearls or even buy their imitation. Natural gems are the rarest and most expensive, while imitation pearls are the least costly. Cultured pearls are somewhere in between.


2. Consider the size of the pearl. Pearls come in all different sizes, from very small to very large. The larger the pearl, the more expensive it will be.


3. Consider the quality of the pearl. Pearls are judged on quality factors, including luster, color, and surface quality. Accessories with higher quality are more expensive.

4. Consider your budget. Pearls can be expensive, so it's essential to set a budget before shopping.


5. Consider your needs. Are you looking for a pearl necklace, earrings, or bracelet? Or do you need loose pearls for another project? Keep your needs in mind when shopping to ensure you get the correct type of pearl.


Keep these things in mind when searching for the perfect pearls, and you'll find what you're looking for in no time.