Pearl Farming: Bringing the Culture to Cultured Pearls
Ever wonder where cultured pearls come from? Sure, you know that they’re ones that come from pearl farms, but do you really know what pearl farming is all about? It’s actually quite a careful and time consuming process; especially when the pearl farmers want to create the highest level of pearl quality.
Let’s start with the basics. Pearls come from oysters. Pearl farms keep thousands of pearl-producing oysters under ideal conditions over about two to five years until a pearl is able to form.
Just like farming crops and livestock, there is a great deal of luck and skill needed to create a profitable “harvest”. Just as there are risks with drought in growing crops, and disease with livestock, entire beds of oysters can be decimated by factors that are just as uncontrollable. Such devastating elements include:
- Intense storms
- Temperature extremes
- Pollution in the water
- Other unpredictable circumstances
Though there are many actions that can be taken in order to reduce the risk posed by these threats, pearl farming is still considered to be a hazardous way to earn a living.
But assuming that all goes well, there is a process to having an oyster or freshwater mussel create a pearl. The procedure begins with the procurement of the oysters themselves. Both Japanese and Chinese pearl farmers typically breed their own akoya oyster stock on their farms from year to year. However farmers of the larger, more exotic saltwater oyster breeds in French Polynesia, Northern Australia and the Philippeans continue the practice of harvesting a strictly limited amount of wild oysters from the oceans each year to fertilize their existing stocks; this maintains genetic diversity within their farms, helping the farmed oysters remain strong and healthy and able to resist many of the common diseases that can plague over-crowded pearling farms.
Today, oysters are usually bred for making the pearls by collecting oyster eggs and sperm, and fertilizing them to produce new oyster larvae. Oyster larvae, or "spat", spend the first few weeks of their lives in a free float, until they reach the point in their development where they find a solid surface to cling to. In nature, this would likely be a rock or other similar spot, but in oyster farms, there are “collectors” provided as surrogate rocks. There, they are monitored until the spat develop into young oysters.
Since we all know that babies belong in nurseries, oyster farms have oyster nurseries, where they spend their first couple of years growing and developing in safe and comfortable conditions.
At about two years of age, they are considered old enough to nucleate. What is nucleation, you ask? To answer this question, you need to first understand that oysters develop pearls in the wild as a result of a reaction they have to shell, bone, coral or parasite that has invaded them and irritates the soft tissue, causing the oyster to produce secretions called "nacre” which envelopes the foreign object. Over time, the nacre layers build up concentrically around the irritant, eventually forming what we know of as a gleaming, gorgeous pearl!
Therefore, to make sure that the oysters at oyster farms produce a pearl, they need to go through a similar experience. That’s where nucleation comes in. It’s a surgical procedure called "grafting" which implants a foreign object into the oyster.
Nucleation is done in two different ways, depending on if the farm uses freshwater or saltwater oysters.
- Saltwater Oyster – this type of mollusk is nucleated with a mother-of-pearl shell-bead. The bead is coated with a tiny sample of mantle tissue from another oyster. This coated bead is then implanted into the oyster. The pearl grows around the bead in the same way it would occur over the grain of shell or coral in the wild, and will remain inside the pearl forever. The shape of the pearl that is produced is directly related to the shape of the bead, allowing for a variety of outcomes.
- Freshwater Mussel– this mollusk is nucleated in much the same way, except the bead is excluded, using only the sample of mantle tissue. The pearl is generated around the mantle tissue, which eventually deteriorates, leaving a pearl made up entirely of crystalline nacre.
After the mollusks have been nucleated, they are allowed a recovery period, in which time it is determined whether the oyster will expel the implant, become ill from the process, or – most commonly – recover and begin the pearl production process.
From there, the oysters move to oyster beds where they are vigilantly cared for. This can take a few months, or a few years, depending on the conditions and the individual oyster.
When the pearls are ready, they are harvested by the pearl farmers, who extract them from the oysters, wash them, dry them, and sort them into general quality and pearl type categories. From there, they are sold to manufacturers, dealers, and jewelers.