What Are Pearls? Natural, Cultured & Imitation Pearls Explained
Pearls are unlike most other gemstones. Rather than being mined from the earth and then cut or polished, they form inside living molluscs and can be used in jewellery much as they grow.
The terminology can be confusing. Natural pearls, cultured pearls and imitation pearls are different things, while freshwater, Akoya, Tahitian and South Sea describe different types of genuine cultured pearls. With antique and vintage jewellery there is another complication: the age of the setting does not necessarily tell you the origin or age of the pearls.
This guide explains the main differences, how pearls form, how their quality is assessed and what to look for when buying older pearl jewellery.
Jump to a section
- What Is a Pearl?
- Natural, Cultured and Imitation Pearls
- How Do Natural and Cultured Pearls Form?
- Freshwater, Akoya, Tahitian and South Sea Pearls
- Can You Tell If Pearls Are Real at Home?
- How Do Laboratories Identify Pearls?
- Pearls in Antique and Vintage Jewellery
- What Determines Pearl Quality?
- What to Look for When Buying Pearl Jewellery
- FAQs
- You Might Also Like
- Final Thoughts
- About Ps Its Vintage
- References
What Is a Pearl?
A pearl is an organic gem produced inside certain molluscs, including oysters and mussels. Many familiar jewellery pearls are made largely from nacre, the iridescent material that can also line the inside of a mollusc shell.
As layers of pearl material develop, their structure interacts with light to create lustre. Some pearls also show overtones or a subtle rainbow-like effect known as orient.
Pearls are not limited to the traditional round white form. Depending on the mollusc and growing conditions, they can be cream, pink, peach, silver, grey, green or gold and can range from almost perfectly round to drop-shaped, oval or irregular baroque forms.
Natural, Cultured and Imitation Pearls
The most useful starting point is to separate pearls into three broad categories.
Natural pearls form inside a mollusc without deliberate human intervention.
Cultured pearls also form inside a living mollusc, but people deliberately initiate the pearl-forming process. They are genuine pearls, not artificial ones.
Imitation pearls are manufactured to resemble pearls rather than being grown as pearls inside a mollusc. They may be made from glass, plastic, shell or another material with a pearl-like coating.
This is why the description “real pearl” only tells part of the story. A cultured pearl is real, but it is not a natural pearl.
Imitation pearls can also have their own place in vintage jewellery. Some older examples are well made and entirely appropriate to period costume pieces. What matters is that they are identified for what they are.
How Do Natural and Cultured Pearls Form?
Natural pearls
A natural pearl develops without deliberate human intervention. A pearl sac forms within the mollusc and layers of pearl material grow over time. Injury, displaced pearl-producing cells or another natural disturbance may be involved, and the exact starting point is not always known.
The familiar idea that every natural pearl begins with a grain of sand is therefore too simple. Historically, natural pearls were found by chance in wild molluscs, and many might be opened before a jewellery-quality pearl was discovered.
Cultured pearls
With cultured pearls, people deliberately start the process. The technique depends on the type of pearl being produced.
Many saltwater cultured pearls are bead nucleated. A round bead is inserted together with a small piece of mantle tissue, after which the mollusc deposits pearl material around the nucleus.
Freshwater cultured pearls have traditionally often been tissue nucleated without a round bead, although modern freshwater production also includes bead-nucleated pearls.
Not every cultivation attempt produces a usable pearl, and pearls grown under similar conditions can still differ in colour, shape, surface and lustre.
Freshwater, Akoya, Tahitian and South Sea Pearls
Freshwater and saltwater describe the environment and mollusc in which the pearl is produced. They are not quality grades.
Freshwater cultured pearls
Freshwater pearls are grown mainly in freshwater mussels and occur in a particularly wide range of shapes and colours. White and cream are common, along with natural pink, peach and lavender tones.
Modern freshwater pearls can be round, large and highly lustrous, so freshwater should not automatically be taken to mean inexpensive or poor quality.
Akoya cultured pearls
Akoya pearls are closely associated with the classic round white pearl necklace. They are generally smaller than Tahitian and South Sea pearls and are known particularly for bright, sharp lustre.
Tahitian cultured pearls
Tahitian pearls are produced by the black-lipped pearl oyster. Although often called black pearls, their natural colours can include grey, silver, green and brown with a range of colourful overtones.
South Sea cultured pearls
South Sea pearls are among the largest cultured pearls regularly used in jewellery. They are best known in white, silver and golden colours and often have a softer, satiny lustre.
These categories describe pearl type, not overall quality. Each can range considerably in quality, appearance and value.
Can You Tell If Pearls Are Real at Home?
You can sometimes spot an obvious imitation by looking closely at the surface and drill holes. Coated imitation pearls may show peeling, chipping or a different material underneath, while genuine nacre often has subtle surface variation.
These are clues rather than proof. High-quality imitation pearls can be convincing, and genuine cultured pearls can be very smooth and closely matched.
The commonly suggested tooth test involves rubbing a pearl against the teeth to feel for a slightly gritty texture. I would not rely on this. It cannot distinguish a natural pearl from a cultured pearl and is unnecessary when jewellery can be examined more carefully.
No home test can reliably establish that a genuine pearl is natural rather than cultured.
How Do Laboratories Identify Pearls?
The difference between natural and cultured pearls is often found inside the pearl rather than on its surface.
Gemmological laboratories use visual examination together with techniques such as X-radiography to examine internal growth structures without cutting the pearl open. These structures can help distinguish natural pearls from bead-nucleated and non-bead cultured pearls.
Further testing can also be used to investigate treatments and colour origin where necessary.
This becomes particularly important when a pearl is being sold as natural and that identification has a significant effect on rarity or value. The age and appearance of the jewellery may provide useful context, but they do not replace laboratory evidence.
Pearls in Antique and Vintage Jewellery
Pearls have been used in jewellery for centuries. Small seed pearls appear in Georgian and Victorian pieces, while pearls also feature prominently in Edwardian and Art Deco jewellery and in later twentieth-century necklaces, rings, brooches and earrings.
Dating the jewellery is useful, but it does not automatically identify the pearls within it.
An antique jewel may contain natural pearls, imitation pearls or pearls that were replaced later in its life. Necklaces are frequently restrung, and clasps and individual pearls can also be changed.
Cultured pearls are not purely modern either. Commercial pearl cultivation became established during the early twentieth century, so vintage jewellery can quite legitimately contain cultured pearls.
When examining an older piece, look at the whole jewel: its metal, hallmarks, construction, settings, clasp, stringing, wear and evidence of alteration. Those details help build a history of the piece, but they should not be used on their own to claim that a pearl is natural.
What Determines Pearl Quality?
The Gemological Institute of America uses seven pearl value factors: size, shape, colour, lustre, surface, nacre and matching.
- Lustre: the brightness and quality of the reflections from the pearl. Strong lustre gives a pearl depth and a lively appearance.
- Surface: pearls can have pits, bumps, wrinkles and other natural characteristics. Fewer or less obvious surface features are generally preferred when other factors are equal.
- Size: larger pearls tend to be rarer within the same pearl type, but size alone does not determine quality.
- Shape: pearls can be round, near-round, oval, button, drop or baroque. Round pearls are difficult to produce, but irregular pearls can also be highly desirable.
- Colour: this includes the main body colour as well as any overtone or orient visible across the surface.
- Nacre: nacre quality affects both appearance and durability in nacreous pearls.
- Matching: in earrings, necklaces and other multi-pearl jewellery, the pearls should work together in size, colour, shape, lustre and surface where a matched appearance is intended.
What does AAA pearl quality mean?
Pearls are often advertised with grades such as A, AA or AAA, but there is no single universal AAA grading system used by every seller. The criteria can differ from one business to another.
It is therefore more useful to look at the qualities behind the grade, particularly lustre, surface, nacre and matching, than to rely on the letters alone.
Are baroque pearls lower quality?
No. Baroque simply describes an irregular shape. A baroque pearl can still have excellent lustre, colour and surface quality.
Perfectly round pearls are generally harder to produce and may attract a premium when other factors are comparable, but shape is only one part of pearl quality.
What to Look for When Buying Pearl Jewellery
Begin with the pearls rather than the label attached to them. Look for lively lustre, examine the surface and consider whether marks are minor characteristics or signs of damage and wear.
With a necklace or bracelet, look at how well the pearls work together. A traditional strand may be closely matched, while a graduated or baroque design should still look balanced.
Check the stringing as well. Knots between pearls help reduce rubbing and can limit how many pearls are lost if the thread breaks. An older strand may simply need restringing rather than replacing.
The clasp can be important too. Antique and vintage pearl necklaces sometimes have particularly attractive gold, silver or gem-set clasps. These can add interest and value to the complete necklace, although the age of the clasp does not prove the origin of the pearls.
If a piece is being sold specifically as containing natural pearls, particularly where that claim materially affects the price, ask what supports the identification.
For more general advice on examining older jewellery, see How to Tell if Vintage Jewellery Is Real – A Simple Guide.
FAQs
Yes. Cultured pearls are genuine pearls grown inside living molluscs. People deliberately initiate the process, which is what distinguishes them from natural pearls.
Yes. Freshwater cultured pearls are genuine pearls grown in freshwater molluscs. Freshwater does not mean artificial or imitation.
A natural pearl forms without deliberate human intervention. A cultured pearl forms after people deliberately initiate pearl formation inside the mollusc.
Not necessarily. Antique jewellery can contain natural, cultured or imitation pearls, and pearls may have been replaced during the life of the piece. Age alone does not establish natural origin.
Usually not with certainty. Gemmological laboratories examine internal structures using techniques including X-radiography to help distinguish natural from cultured pearls.
No. AAA and similar grading terms can be seller-specific. Check what the grade actually means and look at the individual pearl quality factors rather than relying on the letters alone.
Yes, they can be. Baroque describes an irregular pearl shape. Both natural and cultured pearls can occur in baroque forms.
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This is the first guide in a wider pearl series. The next article looks more closely at freshwater, Akoya, Tahitian and South Sea cultured pearls and the differences between them.
Final Thoughts
Pearl terminology becomes much easier once the basic distinction is clear. Natural and cultured pearls are both genuine pearls; imitation pearls are manufactured to resemble them.
From there, the more useful questions are about the individual pearl: what type it is, how good its lustre and surface are, whether it has been altered or treated and, with an older jewel, whether the pearls are likely to be original to the piece.
That approach is more useful than assuming an antique pearl must be natural or that a cultured pearl is somehow less genuine. With pearls, accurate identification and individual quality matter far more than the label alone.
Please note: This guide is provided for general information only. Every effort is made to check the information against recognised sources, but pearl identification from photographs, appearance or simple home tests is not conclusive. Where natural origin, treatment or identification materially affects the value of a pearl or piece of jewellery, appropriate examination or gemmological laboratory testing should be considered.
About Ps Its Vintage
Ps Its Vintage is independently run and specialises in preloved, vintage and antique jewellery. I sell rings, chains, brooches, bracelets, earrings, lockets, charms and other one-off pieces, with new jewellery added as I find it.
Each item is described with the available information about its materials, hallmarks, gemstones, measurements, age and condition, so you can see what you are buying before it arrives.
More about the business can be found on the About Ps Its Vintage page.