When most people think of pearls, they imagine divers finding gleaming gems inside oysters deep in the ocean. While natural wild pearls do exist, the vast majority of pearls today are cultured pearls - grown with the careful help of human hands on pearl farms. Cultured pearls are 100% real pearls, but their creation is a fascinating blend of nature and human intervention. In this post, we’ll explore how freshwater, Akoya, and Tahitian pearls are cultivated. Understanding the journey from oyster (or mussel) to jewel will give you a new appreciation for the pearls in your jewellery box!
Cultured Pearls: A Partnership with Nature
All three types - Freshwater, Akoya, and Tahitian pearls - are cultured pearls. This means that humans play a role in starting the pearl-making process, but after that, it’s up to the mollusc (oyster or mussel) to do the miraculous work of creating the pearl.
Culturing pearls began in the early 20th century when pioneers like Kokichi Mikimoto in Japan figured out how to encourage oysters to form pearls on demand. Before that, pearls were only obtained by chance (and many oysters had to be sacrificed to maybe find one pearl). The advent of pearl farming made pearls more accessible and ensured oysters could be treated more sustainably.
Here’s an overview of how pearl cultivation works:
1. Seeding/Nucleation - The Beginning of a Pearl:
In the wild, a pearl forms when an irritant (like a tiny parasite or a piece of shell) gets inside an oyster and the oyster coats it with nacre. In pearl farming, technicians recreate this process in a controlled way. For Akoya and Tahitian pearls (and other saltwater pearls), the process involves surgically implanting a small bead nucleus along with a tiny piece of donor mantle tissue into the oyster. The bead is often made from polished shell and serves as the seed that the pearl will form around. The piece of mantle tissue (from a “donor” oyster) is what triggers the oyster’s mantle to start secreting nacre. The technician makes a tiny incision in the oyster’s body (specifically, the gonad area) and slides in the bead and tissue piece with precision. This is a very delicate procedure, oysters are sensitive creatures, and not all survive this operation. Those that do will hopefully accept the implant and begin to deposit nacre over it, forming a pearl layer by layer.
Freshwater pearls, which are grown in freshwater mussels, are nucleated a bit differently. Traditionally, most freshwater pearls were nucleated with only a piece of mantle tissue and no bead. The mussel’s mantle is cut and a tiny bit of donor mantle is inserted into small slits in the host mussel’s mantle. Each freshwater mussel can be implanted in many spots, often 12 to as many as 30-40 insertions across both shells. That’s why one freshwater mussel can produce many pearls at a time, unlike saltwater oysters which typically yield one pearl per oyster. (Some newer freshwater pearl techniques do use beads for larger pearls, but tissue nucleation is still common, especially for the classic small freshwater pearls.)
After nucleation, the molluscs are returned to the water and given time to recover. There is an initial period of a few weeks when the oyster/mussel is very vulnerable, it may expel the nucleus or simply fail to thrive if stressed. Farmers often keep the newly operated oysters in protective baskets and calm water conditions until they show they’re healthy and the nucleus is stable.
2. The Cultivation Period - Patience and Care:
Once the nucleus is accepted, it’s mostly up to nature. The mollusc will slowly secrete nacre around the nucleus, forming the pearl. This process takes time and exactly how long depends on the type of pearl:
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Akoya Pearls (Japan): Akoya oysters are small, so they produce smaller pearls relatively quickly. Akoya pearls are typically grown for 8 to 18 months. Some may be harvested in under a year if they’ve reached a good size and quality, while others are left longer for thicker nacre. Akoya pearls in that time usually grow to about 6-9 mm. Because they’re in cooler waters and the oysters are small, the nacre layers accumulate more slowly (about 0.3 mm of nacre per year on a bead on average). Japanese winters are cold, and oysters often go semi-dormant, which can enhance nacre quality but means patience is needed.
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Tahitian Pearls (French Polynesia): Tahitian pearls come from the black-lipped oyster (Pinctada margaritifera), which is much larger than an Akoya oyster. These are cultivated in warm lagoon waters. Tahitian pearls are generally grown for 18 to 24 months. In that period, they can reach sizes of 8-14 mm, sometimes even larger. The growth rate can be around 1-2 mm of nacre per year - faster than Akoya, thanks to warm water and a big oyster, but since a thicker nacre coating is often desired, they let them grow at least 1.5 years or more. The result is those gorgeous dark pearls with overtones of green, blue, aubergine, etc. Tahitian oysters are kept in baskets or on lines in lagoons, where they filter plankton from the nutrient-rich Pacific waters.
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Freshwater Pearls (China): Freshwater mussels, such as the commonly used triangle mussel, are robust and can produce many pearls at once. The cultivation time for freshwater pearls can vary widely. Many freshwater pearls are grown for about 2 to 5 years before harvest. Some small pearls might be harvested after just 1 to 2 years, especially if the goal is a smaller size or if using newer bead-nucleation techniques. But for traditional tissue-nucleated freshwater pearls, 3-4 years is common to get a nice size and lustre, and some pearls left even longer can grow quite large or develop very thick nacre. Freshwater mussels are often nucleated in their second year of life and harvested by around age 5 or 6. They live in rivers or ponds on farms, usually suspended in mesh bags or cages, or sometimes in controlled ponds where farmers can tend them easily. One interesting aspect: since no round bead is typically used, freshwater pearls are pure nacre - which is why many can be baroque or odd-shaped, but it also means if left longer, they can become quite large (over 10mm) with solid nacre.
During the cultivation period, pearl farmers must care for the molluscs diligently. They regularly clean the shells of fouling organisms (like algae or barnacles) that could stress the oysters. They move them as needed to ensure good water quality and plankton flow. They might transfer oysters to different depths or areas as seasons change, to find the optimal temperature and food conditions. Essentially, the farmers create a “spa” for oysters because a healthy, happy oyster is more likely to produce a high-quality pearl. It’s truly a labour of love; farmers invest a lot of time and effort while waiting for the pearls to form, with no absolute guarantee of how each pearl will turn out.
3. Harvesting the Pearls:
When the time is right (farmers gauge this by experience, and sometimes by sacrificing a test oyster to examine a pearl’s development), the pearls are harvested. Each oyster or mussel is opened carefully. For saltwater pearls, the pearl is usually in the oyster’s gonad and is removed with a special instrument. At this point, that oyster’s journey might not be over, many saltwater oysters can be nucleated again. Often, an oyster that produced a good pearl will be implanted with a new (sometimes larger) bead promptly and returned to the water for another 1-2 years for a second pearl. Some exceptional oysters might even produce a third pearl in their lifetime. However, oysters generally don’t live forever, and after a couple of operations they may be retired.
The moment of harvest is full of suspense, farmers finally get to see the fruits of years of work. Not every pearl will be a beauty. In fact, a given harvest will include many pearls that are off-shape, or with blemishes, or low lustre. Only a smaller percentage will be gem-quality that can be used for high-end jewellery. This rarity of fine pearls is one reason they command significant prices. For example, out of an entire harvest of Tahitian oysters, maybe only 5% might be round, high-lustre, top-colour pearls (and an even tinier percentage will be the truly large, flawless ones). The rest still have uses -baroque pearls are turned into more affordable and artistic jewellery, heavily blemished pearls might be carved or dyed or used in costume jewellery, and some pearls might even be ground up for cosmetic or medicinal use (in some cultures). Virtually nothing is wasted.
4. Sorting and Matching: (This is after cultivation, but worth mentioning.) Once pearls are harvested, they undergo cleaning (simply washing and gently buffing to remove residue). Then they are graded and sorted by size, colour, shape, lustre, etc. This can take months for a big harvest, as thousands of pearls are grouped into lots that match, especially for strands. This stage is also crucial for the pearl’s journey to market - pearls often change hands from farmers to wholesalers to jewellery makers, and at each step, they are evaluated on those quality factors we discussed in the previous post about value.
Sustainable and Ethical Pearl Farming
One of the beautiful aspects of pearl cultivation is that it can be done in harmony with nature. In fact, pearl farming requires a healthy environment – oysters won’t produce lovely pearls in polluted or hostile waters. The best pearl farms are like stewards of their environment, often far out in pristine bays or lagoons, constantly monitoring water quality, and tending to not just the oysters but the ecosystem around them. Unlike some other forms of aquaculture, pearl farming can have a low environmental impact. There are no heavy chemicals or feeds as oysters filter plankton naturally. A well-managed pearl farm can even contribute to water cleanliness, as each oyster filters particulates from the water as it feeds.
Ethical treatment of oysters is also important. Think about it: an oyster’s health directly determines the pearl quality. So, pearl farmers have a strong incentive to keep their molluscs healthy and stress-free. This isn’t a factory-farming situation; it’s more akin to beekeeping or caring for a coral reef. Saltwater oysters can be reused, and even when they reach the end of their pearl-producing days, many farms “retire” them by returning them to the wild or using them for breeding future generations of oysters. At Raison d’Être, for example, we ensure that our pearl suppliers follow strict ethical practices, such as limiting the number of pearl operations per oyster. Typically, an oyster in our supply chain will produce no more than 2-3 pearls in its lifetime before it’s allowed to retire - this prevents over-stressing the creature.
Furthermore, pearl farming often provides sustainable livelihoods for coastal communities. In places like Polynesia, many pearl farms are family-run, passed down through generations. These communities have a vested interest in protecting their coastal waters and reefs, which aligns with producing great pearls. It’s a symbiotic relationship: pearls give economic reason to preserve the environment.
It’s worth noting that no gemstone is more renewable or sustainable than pearls. As one environmental researcher put it, pearls are the only gem that come from a living creature and are renewable within a human timescale. You don’t have to strip-mine a mountain or pan a river to get pearls, you encourage and nurture life in the water. In an era where consumers care about sustainability and ethical sourcing (as we do deeply at Raison d’Être), pearls shine as an example of responsible luxury.
From Farm to Fashion: The Wonder of Cultured Pearls
Considering the journey: a tiny bead and piece of tissue go into an oyster; a couple of years of quiet work under the water; then a gleaming pearl emerges, it feels almost magical. Each pearl is a little bit of nature’s art, shaped by the character of the water it grew in and the individual oyster that made it. Tahitian pearls carry the mystery of tropical lagoons in their orient; Akoya pearls embody the subtle beauty of Japanese seas; freshwater pearls reflect the gentle hues of lakes and rivers.
No two pearls are exactly alike, which is part of their charm. Even expert farmers can’t control the exact colour or iridescence a pearl will have. This unpredictability is why pearls are often seen as symbols of uniqueness and serendipity. It’s also why one might sort through dozens of pearls to find the one that “speaks” to them.
When you wear a piece of pearl jewellery, you are essentially wearing a piece of the ocean’s history - a gem that grew slowly in sync with tides and seasons, tended by human hands in partnership with nature. It’s a treasure that didn’t require destruction to obtain, but rather cultivation and care. In a fast-paced world, the creation of a pearl is a slow, deliberate process, and that is part of what makes it so special and precious.
Explore Our Pearl Collections with New Appreciation
Knowing how pearls are cultivated can enhance your enjoyment of pearl jewellery. When you admire the stunning colours of a Tahitian pearl pendant, you might picture the crystal-clear lagoons where divers and farmers tend to their oysters under the Pacific sun. And when you put on a pair of pretty freshwater pearl earrings, you might think of the serene lakes in China and the skilled technicians who implanted and harvested those pearls.
Every Maya Sienna pearl piece at Raison d’Être carries this story within it. We are proud to source our pearls from farms that uphold the highest standards of sustainability and craftsmanship. Our partners ensure that the waters remain clean and the oysters are healthy, which not only yields better pearls, but is better for the planet. By choosing cultured pearls from ethical sources, you’re supporting a cycle of responsible luxury.
From ocean (or river) to ornament, the path of a pearl is an incredible journey. And when that journey ends with you, as a beautiful piece of jewellery adorning your life’s moments, the story truly comes full circle. Enjoy your pearls and wear them with pride, knowing the wonder of nature and human care that brought them to you.