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Pearl Buying Guide: Freshwater, Saltwater, Lustre, Size, and How to Spot Fakes
Pearls are the only gem made by a living creature, and they are also one of the most confusing to buy. This guide explains freshwater and saltwater pearls, what lustre really means, how size and shape affect price, and the simple tests that separate real pearls from imitations.
A pearl looks simple. A round white bead, a soft glow, a strand that has been a symbol of quiet elegance for centuries. Behind that simplicity is a market full of distinctions that matter enormously to price and to how a piece will wear: freshwater versus saltwater, natural versus cultured, lustre versus surface shine, knotted versus unknotted strands. A buyer who does not know these distinctions can easily pay a saltwater price for a freshwater strand, or buy an imitation believing it is real.
This guide explains each distinction in plain language, with no prior knowledge assumed. It covers how pearls are formed, the four main types you will actually encounter in shops, the seven qualities professionals use to judge a pearl, how to tell a real pearl from a fake one, and how to choose a piece that suits the way you will wear it. Prices are given as typical ranges as of November 2026, because pearl prices vary with size, quality, and retailer. Anyone quoting a single fixed price for a whole category is selling, not informing.
How Pearls Are Made: Natural, Cultured, and Imitation
A pearl forms when a mollusc coats an irritant — a grain of sand, a parasite, a bead inserted by a farmer — with layer upon layer of nacre, the iridescent substance that lines a shell. A natural pearl forms without human intervention, and it is extremely rare and expensive; almost no natural pearl strands are sold in ordinary jewelry shops, and a natural pearl strand can cost many thousands of dollars. Nearly every pearl sold today is cultured, which means a farmer inserted the irritant deliberately and the mollusc did the rest. A cultured pearl is a real pearl. The word cultured describes how it started, not whether it is genuine.
Imitation pearls are a different thing entirely. They are usually glass or plastic beads coated with a pearlescent paint or a fish-scale essence, and they contain no nacre at all. They can look convincing in a photograph or in a shop window, and they are perfectly acceptable as costume jewelry at costume prices — typically around $10 to $40 for a strand as of November 2026. The problem is only when an imitation is sold at a real-pearl price, which happens more often than buyers expect, especially online. The tests later in this guide are the defence against that.
Freshwater Versus Saltwater: The Four Pearls You Will Meet
Freshwater pearls are grown in mussels in lakes and rivers, mostly in China. A single mussel can produce many pearls at once, which makes freshwater pearls the most affordable real pearls. They are almost always solid nacre all the way through, because they are grown without a bead nucleus, which makes them durable. Their shapes are often slightly off-round — oval, button-shaped, or softly irregular — and their lustre is soft and satiny rather than sharply reflective. A freshwater strand typically runs around $100 to $500 for a good-quality 7 to 8 millimetre strand as of November 2026, and a single freshwater pendant can be found for around $50 to $150.
Saltwater pearls come in three main types. Akoya pearls, grown in Japan and China, are the classic white round pearl of the traditional strand: small, usually 6 to 8 millimetres, very round, with a bright mirror-like lustre. A good Akoya strand typically runs around $300 to $1,500 as of November 2026. South Sea pearls, grown in Australia, Indonesia, and the Philippines, are the largest pearls, typically 9 to 15 millimetres, in white, silver, and golden colours, with a soft satiny lustre; a strand can run around $1,000 to $10,000 or more. Tahitian pearls, grown in French Polynesia, are naturally dark — grey, green, peacock, and black — and typically 8 to 12 millimetres; a strand typically runs around $500 to $5,000 as of November 2026. Each type has its own character, and none is objectively better than the others; the right choice depends on the size, colour, and budget you want.
| Pearl type | Water | Typical size | Colour | Typical strand price* | Best for |
|---|---|---|---|---|---|
| Freshwater | Lakes and rivers | 6–9 mm | White, pink, peach, lavender | Around $100–$500 | Everyday wear; a first strand |
| Akoya | Saltwater | 6–8 mm | White, rose overtone | Around $300–$1,500 | The classic white strand |
| South Sea | Saltwater | 9–15 mm | White, silver, gold | Around $1,000–$10,000+ | A large, luxurious strand |
| Tahitian | Saltwater | 8–12 mm | Grey, green, peacock, black | Around $500–$5,000 | Dark, dramatic colour |
*Typical ranges for good-quality strands of standard length as of November 2026. Exact prices depend on size, lustre, surface quality, and matching.
The Seven Qualities That Determine a Pearl's Value
Professionals judge pearls on seven factors: lustre, surface quality, shape, size, colour, nacre thickness, and matching. Lustre is the most important of all, and it is the quality buyers most often misunderstand. Lustre is not shine — it is the depth of the glow, the sense that light comes from inside the pearl rather than bouncing off its surface. A pearl with high lustre shows a sharp, clear reflection of your face in its surface, like a mirror. A pearl with low lustre shows a blurry, chalky reflection, and looks flat even under bright light. When choosing between two strands at different prices, compare their lustre first; it is what you will actually see every time you wear them.
Surface quality is the second factor: a pearl's surface should be as clean as possible, free of bumps, pits, and wrinkles. Almost no pearl is perfectly clean, and small blemishes are normal, but heavy blemishing lowers the value and is visible in wear. Shape matters too — perfectly round pearls are the rarest and most expensive, while off-round, oval, drop, and baroque shapes are less expensive and often more interesting. Size is measured in millimetres, and price rises steeply with size: a 9 millimetre strand can cost several times what a 7 millimetre strand of the same quality costs, because large pearls take longer to grow and are rarer. Colour includes both the body colour and the overtone, the subtle pink, silver, or green tint that floats over it; overtone is a matter of taste, not quality, and the best choice is the one that flatters the wearer's skin.
Nacre thickness is the quality that determines how long a pearl lasts. A pearl with thick nacre — at least 0.5 millimetres on a saltwater pearl, and solid nacre on a freshwater pearl — will keep its lustre for decades. A pearl with thin nacre can look beautiful when new and then go dull, chalky, or even peel within a few years, because the thin coating wears through. Unfortunately, nacre thickness is the hardest quality for a buyer to judge by eye; the practical defence is to buy from a seller who states it, and to be suspicious of any saltwater pearl sold very cheaply, because thin nacre is the usual reason. Matching is the last factor, and it matters most for strands and earrings: the pearls should be uniform in size, shape, colour, and lustre. A strand where one pearl is visibly larger, darker, or duller than the others is a strand that was not matched carefully, and it will always draw the eye to the mismatch.
How to Tell a Real Pearl From a Fake One
The most reliable simple test is the tooth test. Rub the pearl gently against the edge of a front tooth: a real pearl feels slightly gritty, like fine sandpaper, because its nacre is made of microscopic overlapping plates. An imitation pearl feels smooth and slippery, because its surface is glass or plastic coated with paint. The test is not perfect — a very well-made imitation can feel slightly gritty, and a real pearl that has been coated can feel smooth — but it is a useful first check, and it costs nothing. Do it on several pearls in a strand, not just one, because a strand can mix real and imitation beads.
Other checks help. Real pearls are cool to the touch when first picked up, and they warm slowly in the hand; plastic imitations feel warm immediately and feel light. Real pearls have slight variations in shape and colour from bead to bead, even in a well-matched strand; imitations are often perfectly uniform, which is itself a warning sign. Look at the drill holes, where the thread passes through: a real pearl's drill hole is clean and sharp, while an imitation's coating often chips or flakes around the hole, revealing the glass or plastic underneath. And look at the price: a strand of large, perfectly round, high-lustre pearls sold for a very low price is not a bargain, it is an imitation, because real pearls of that quality cannot be produced that cheaply.
For a significant purchase, the strongest protection is documentation. A reputable seller will state the pearl type, the size, the origin, and whether the pearls are cultured, and will offer a return policy that lets you have the piece checked independently. A pearl grading report from a recognized laboratory is available for high-value strands, and it is worth the cost for a purchase over a thousand dollars. If a seller cannot tell you the pearl type, will not state it in writing, or has no return policy, walk away — the piece is not worth the risk, whatever it looks like.
Choosing a Strand, Studs, or a Pendant
A strand is the classic pearl purchase, and the details matter. Check that the pearls are knotted between each bead: knotting is the mark of a properly made strand, it keeps the pearls from rubbing against each other, and it means that if the thread breaks, you lose one pearl instead of the whole strand. Check the clasp — a good strand has a secure clasp, often with a safety catch, and a clasp that matches the quality of the pearls. And check the length against our guide to choosing a necklace length, because a strand that sits at the wrong point on the neck will not be worn, however beautiful the pearls are. A princess length of 17 to 19 inches is the most versatile for a first strand.
Pearl studs are the most versatile pearl purchase of all, because they are worn more often than any other piece of pearl jewelry and they suit almost every face and every occasion. For studs, matching is everything: the two pearls should be the same size, colour, and lustre, and they should sit symmetrically. A pair of 7 to 8 millimetre Akoya or freshwater studs typically runs around $100 to $400 as of November 2026, and they are a gift that is very hard to get wrong. A pendant is the most forgiving pearl purchase, because a single pearl does not need to match anything; it is also the best choice if you want one beautiful pearl rather than a matched set, and it is the easiest way to wear a larger or more unusual pearl, such as a Tahitian or a baroque freshwater pearl.
How to Care for Pearls So They Last
Pearls are the most delicate common jewelry material, and their care rules are stricter than for any other stone. They are soft — around 2.5 to 4.5 on the Mohs hardness scale — and porous, which means they are damaged by acids, including the acids in perfume, hairspray, lotion, and perspiration. Put pearls on last, after perfume and makeup, and wipe them with a soft cloth after every wearing. Never soak pearls, never clean them with an ultrasonic cleaner, and never use anything stronger than a soft cloth barely dampened with water. Our guide to jewelry care and cleaning covers pearls in detail, and the pearl rules there are the ones to follow without exception.
Store pearls separately from other jewelry, in a soft pouch or a lined compartment, because harder stones — especially diamonds — will scratch them. Keep them away from dry air, which can cause them to crack, and do not store them in a sealed plastic bag or a safe deposit box for long periods, because pearls need a little humidity to stay healthy. Restring a pearl strand every one to two years if it is worn regularly, because the silk thread stretches and weakens, and a strand that breaks in public loses pearls. A jeweler can restring a strand for a modest fee, and it is the single most important maintenance a pearl owner can do.
A Short Checklist Before You Buy
- Know the type: freshwater, Akoya, South Sea, or Tahitian — and ask the seller to state it in writing.
- Compare lustre first: look for a sharp, clear reflection in the pearl's surface, not just a bright shine.
- Check the surface for bumps and pits, and check that a strand is well matched in size, colour, and lustre.
- Do the tooth test on several pearls, check the drill holes for flaking, and feel the weight and temperature.
- Confirm the strand is knotted between each pearl and the clasp is secure.
- Ask about nacre thickness, the return policy, and whether an independent check is welcome.
- For a purchase over $1,000, ask about a laboratory grading report.
The Bottom Line
A good pearl purchase is a lustre purchase. Choose the type that fits your budget and your taste — freshwater for everyday wear, Akoya for the classic strand, South Sea for size, Tahitian for colour — then choose the strand or the pair with the best lustre and the cleanest matching you can afford, and buy it from a seller who states what it is in writing. A pearl bought that way will glow for decades. A pearl bought on price alone, without knowing its type or its lustre, will disappoint within a year, however good it looked in the box.
About the author
Alex Carter is the editor of Lustre Journal. He researches jewelry by reading grading standards, retailer terms, and trade guidance, and by comparing how pieces are actually made, priced, and cared for. He has no commercial relationship with any brand mentioned on this site. Read more on our About page.