Pearls occupy a unique position in the world of jewellery, they are the only gem produced by a living creature, formed not through geological processes over millions of years but through the quiet, patient work of a mollusc responding to its environment. No other jewel has accumulated quite the same weight of cultural history, symbolic meaning, and enduring elegance across civilisations as diverse as ancient Rome, feudal Japan, and the courts of Mughal India. Today, pearls remain as coveted as ever, and increasingly, as relevant in modern jewellery as they are in classical. This guide covers everything you need to know: how pearls form, the key types and their differences, the quality factors that determine value, how to identify real pearls, and how to choose the right piece for yourself or as a gift. Explore our full pearl jewellery collection at Poh Heng.
For pearl styling tips, see our pearl styling guide. For how pearls compare to other gemstones, see our gemstones guide.
How Pearls Form: Nature's Most Patient Creation
A pearl forms when a foreign irritant, a grain of sand, a parasite, or a fragment of shell, enters the soft tissue of an oyster or mollusc. In response, the creature begins coating the irritant with successive layers of a substance called nacre (pronounced "nay-ker"), the same iridescent material that lines the inside of the shell. Layer by layer, over months or years, these microscopic nacre sheets build up around the irritant until a pearl is formed.
Nacre is composed of microscopic platelets of aragonite (a form of calcium carbonate) bound together by an organic protein. It is this layered structure that gives pearls their distinctive lustre, the way light refracts through the translucent nacre layers and reflects back creates the glowing, deep-lit quality that distinguishes a fine pearl from any manufactured imitation. The thicker the nacre, the more luminous and durable the pearl.
Types of Pearls
Natural Pearls
Natural pearls form entirely without human intervention, produced when a wild mollusc naturally encounters an irritant. Because this process is entirely accidental and the resulting pearl must be found by harvesting wild molluscs, natural pearls are extraordinarily rare. The vast majority of natural pearl sources were commercially exhausted during the early 20th century as demand outpaced supply. Today, a natural pearl of significant size and quality is a collector's item commanding substantial prices at auction.
Cultured Pearls
Cultured pearls are produced with human assistance — a process pioneered by Kokichi Mikimoto in Japan in the early twentieth century. Pearl farmers introduce a small bead nucleus (in saltwater pearls) or a piece of mantle tissue (in freshwater pearls) into a live mollusc, which then coats it with nacre in the same biological process as a natural pearl. Cultured pearls represent virtually all pearl jewellery sold today. High-quality cultured pearls are genuinely beautiful and valuable, the culturing process determines the pearl's shape and initial size, but nacre thickness, lustre, and surface quality are determined entirely by the mollusc and its environment.
Saltwater Pearls
Saltwater pearls are cultivated in ocean environments and are generally valued for their superior lustre, rounder shape, and higher nacre quality compared to most freshwater pearls. The main varieties are:
Akoya Pearls: Cultivated primarily in Japan and China, Akoya pearls are regarded as the classic pearl for fine jewellery. Typically ranging from 6mm to 9mm in diameter, they are renowned for their perfectly round shape and exceptional, mirror-bright lustre. Their colour range is predominantly white and cream, often with rose or silver overtones.
South Sea Pearls: The largest of all cultured pearls, South Sea pearls are produced by the Pinctada maxima oyster in the warm waters of Australia, Indonesia, and the Philippines. They range from 10mm to 20mm in diameter and come in white, cream, and golden tones. Their size and the thickness of their nacre give them a distinctive, satiny lustre that sets them apart from other pearl types.
Tahitian Pearls: Cultivated in the black-lipped oyster (Pinctada margaritifera) in the waters of French Polynesia, Tahitian pearls are celebrated for their naturally dark, exotic colours, ranging from deep charcoal and black to vibrant greens, blues, and the prized peacock colour (a deep green with pink and purple overtones). They typically range from 9mm to 14mm in diameter.
Mabe Pearls: Mabe pearls grow against the inner shell of a mollusc rather than within its body tissue. This creates a distinctive domed shape with a flat back, making them ideal for earrings, pendants, and rings where a full-round pearl would be impractical. Poh Heng's pearl jewellery collection includes beautifully crafted Mabe pearl pieces that showcase the pearl's distinctive shape and natural radiance.
Freshwater Pearls
Freshwater pearls are cultivated in lakes and rivers, predominantly in China. Unlike saltwater pearls, which are typically grown one per mollusc, a single freshwater mussel can produce multiple pearls simultaneously, making freshwater pearls more abundant and generally more affordable. They come in a wide range of shapes, from round to oval, button, drop, and baroque, and colours including white, cream, peach, lavender, and pink. Their nacre tends to be thicker than Akoya pearls (since no bead nucleus is used in most freshwater cultivation), though their lustre is generally softer.
Keshi Pearls: Keshi pearls are a byproduct of the culturing process, formed when the mollusc rejects the implanted nucleus and grows a pearl entirely from nacre with no nucleus at all. Because they are solid nacre, keshi pearls have exceptional lustre. They are small and irregular in shape, occurring in both saltwater and freshwater environments, and are prized for their organic, sculptural forms.
Pearl Quality: The Six Factors That Determine Value
Pearl quality assessment considers six key factors. Unlike diamonds, there is no single universal grading standard, most jewellers use an AAA-to-A scale or similar system — but these six criteria apply across all pearl types.
Lustre
Lustre is the most important single indicator of pearl quality. It refers to the quality and intensity of light reflected from the pearl's surface, created by the interaction of light with the layered nacre beneath. A high-lustre pearl displays sharp, bright reflections; you can almost see your reflection in its surface. Low lustre produces a chalky, dull appearance. Lustre is directly related to nacre thickness: thicker, more uniform nacre produces stronger lustre.
Colour
Pearls come in a wide spectrum of body colours, white, cream, pink, silver, gold, green, and black, determined by the mollusc species, the water environment, and the nacre's composition. Many pearls also display overtones: a secondary colour visible over the body colour. A white Akoya pearl with rose overtones, for example, appears warmer and more flattering against most skin tones than a pure white pearl. Colour preference is personal, but consistent, even colour distribution across the pearl is a quality indicator.
Shape
Round pearls are the rarest and most valuable shape for traditional jewellery, a perfectly spherical pearl is genuinely difficult to produce naturally. Other desirable shapes include near-round, button (flattened), drop (teardrop), and oval. Baroque pearls, irregularly shaped, are appreciated in contemporary jewellery for their uniqueness and organic character, and are often more affordable than round pearls of similar lustre and surface quality.
Blister pearls form attached to the inside of the mollusc's shell rather than freely within its tissue, producing an irregular, half-dome shape with a flat back, used primarily in artistic and decorative jewellery.
Size
Pearl size is measured in millimetres (diameter). Larger pearls are rarer and more valuable, all else being equal, producing a large pearl requires a larger mollusc, a longer cultivation period, and a good deal of biological fortune. Size perception also depends on shape: an elongated oval may feel larger than a round pearl of the same millimetre measurement. For jewellery purposes, the "right" size is ultimately the one that is proportionate to the wearer and the setting.
Surface Quality
Surface quality refers to the presence and visibility of blemishes, pits, spots, or irregularities on the pearl's surface. No pearl is entirely blemish-free, minor surface characteristics are natural and generally acceptable. Pearls with a smooth, clean surface are more valuable; the key question is whether any blemishes are visible to the naked eye and whether they affect the pearl's structural integrity or beauty.
Nacre Thickness
Nacre thickness directly affects both lustre and durability. A thin nacre layer produces weaker lustre and a pearl that may peel or dull more quickly over time. For Akoya pearls especially, nacre thickness is a critical quality factor, cheaper specimens may have nacre so thin that the bead nucleus is visible as a chalky line when the pearl is held to a light. Freshwater pearls, which are typically grown without a nucleus, tend to have thicker nacre as the entire pearl is composed of it.
Pearl Jewellery: From Classic to Contemporary
Pearl jewellery spans every type and occasion. At Poh Heng, our pearl collection includes pieces across all major jewellery categories:
Pearl Necklaces: From a single-pearl pendant on a fine gold chain to a multi-strand graduated pearl strand, pearl necklaces are the most iconic and recognisable form of pearl jewellery. Length determines the styling effect: choker lengths read as modern and bold; princess lengths (around 45cm) are the most versatile; opera lengths offer the most styling flexibility.
Pearl Earrings: Pearl stud earrings are the single most universally flattering and occasion-appropriate pearl jewellery piece, suitable for everything from a daily commute to a formal event. Pearl drop and dangle earrings add movement and drama for more statement occasions.
Pearl Bracelets: A classic pearl bracelet is one of the most elegant ways to incorporate pearls into an everyday look, pairing beautifully with watches and other fine jewellery.
Pearl Pendants: A single pearl pendant, whether a perfectly round Akoya pearl or a distinctive baroque or Mabe pearl, is a versatile, modern way to wear pearls that feels contemporary rather than traditional.
Pearls are also a beautiful and culturally meaningful gift choice in Singapore and across Asia. Browse our gifts for her collection for curated pearl gift ideas suitable for graduations, birthdays, and special milestones.
How to Identify Real Pearls
The Tooth Test
The most reliable at-home test for identifying real pearls is the tooth test: gently rub the pearl against the edge of your tooth. A real pearl, whether natural or cultured, will feel slightly gritty or sandy due to the microscopic platelet structure of its nacre surface. An imitation pearl (made of glass, plastic, or coated beads) will feel smooth and frictionless because it lacks the layered nacre structure.
Weight and Temperature
Real pearls feel slightly cool to the touch initially, they warm slowly from body heat. Imitation pearls made of plastic warm almost instantly. Real pearls are also typically heavier than plastic imitations of the same size, due to the density of nacre.
Visual Inspection
Under close inspection, real pearls show natural variations in lustre and surface, no two real pearls are exactly identical. Imitation pearls tend to look too uniform in their surface finish, often with a distinctly artificial sheen rather than the deep, glowing lustre of real nacre. The drill hole on a real pearl will show a clean nacre edge; on an imitation, the coating may chip or peel at the edge.
Why It Matters
While imitation pearls can be affordable and decorative, they lack the depth of lustre, durability, and inherent value of real pearls. If you are purchasing pearl jewellery as an investment, a meaningful gift, or a piece to be worn and cherished for years, ensuring authenticity is essential. Purchasing from a reputable jeweller such as Poh Heng is the most straightforward assurance of quality.
Caring for Pearl Jewellery
Pearl jewellery requires more careful attention than most other gemstones due to pearls' organic nature and relative softness.
Put pearls on last: Always apply perfume, hairspray, and cosmetics before wearing pearl jewellery, as these products contain acids and chemicals that erode nacre over time.
Wipe after each wear: Gently wipe pearl jewellery with a soft, dry cloth after wearing to remove perspiration and oils before storing.
Avoid water and chemicals: Do not wear pearl jewellery while swimming, showering, or cleaning. Keep pearls away from chlorine, bleach, and acid-based products.
Store flat and separately: Store pearl necklaces flat rather than hanging, to prevent the thread from stretching. Store separately from other jewellery to prevent harder stones from scratching the nacre surface.
Re-string pearl necklaces periodically: Pearl strands strung on silk should be professionally re-strung every one to three years, depending on frequency of wear. Silk weakens over time and a broken strand can mean lost pearls.
For professional pearl cleaning, re-stringing, and jewellery maintenance, visit Poh Heng's Jewellery Services at any of our islandwide boutiques.
Pearls in History and Culture
Pearls have been prized across virtually every major civilisation throughout recorded history. In ancient Rome, pearls were the ultimate symbol of wealth and status, so valuable that Julius Caesar reportedly issued laws restricting their use to the ruling classes. In Asia, pearls have carried deep symbolic meaning for millennia: in Chinese culture, they represent wisdom acquired through experience; in Japanese tradition, they are associated with purity and tears of joy; across the Islamic world, pearls have long been regarded as the perfect gem, referenced in the Quran as one of paradise's adornments. The Mughal emperors of India accumulated legendary pearl collections; the rulers of the Arabian Gulf built their economies on pearl diving for centuries before oil was discovered.
The development of cultured pearl technology by Mikimoto in the early twentieth century democratised access to pearl jewellery, making it possible for people beyond royalty and the very wealthy to own and wear genuine pearls. In Singapore and across Southeast Asia, pearls remain deeply embedded in gifting and bridal traditions, associated with grace, purity, and a considered kind of elegance that transcends passing fashion.
Closing Thoughts
Pearls are unlike any other gem, in how they are formed, in what they mean across cultures, and in the enduring quality of their beauty. Whether you are drawn to the classic elegance of a round Akoya pearl, the exotic drama of a Tahitian, the generous warmth of a South Sea, or the creative freedom of a baroque freshwater pearl, the right pearl is the one that resonates with you.
Explore our full pearl jewellery collection online, or visit any of our islandwide Poh Heng boutiques where our team can help you find the perfect pearl piece, for yourself or as a meaningful gift for someone you care about.
Frequently Asked Questions
What is the difference between natural and cultured pearls?
Natural pearls form entirely without human intervention when a wild mollusc encounters a natural irritant, they are extremely rare and valuable. Cultured pearls are produced with human assistance, by inserting a nucleus or tissue piece into a farmed mollusc to stimulate nacre production. Both natural and cultured pearls are genuine pearls composed of real nacre; the difference is in origin and rarity, not in the pearl's material composition.
What is the difference between freshwater and saltwater pearls?
Saltwater pearls, including Akoya, South Sea, and Tahitian varieties, are cultivated in oceans and are generally valued for their superior lustre, rounder shape, and more uniform nacre. Freshwater pearls are cultivated in lakes and rivers (primarily in China) and offer greater variety in shape, colour, and size at more accessible price points. Both are genuine pearls; the choice between them depends on the look, budget, and jewellery type you are considering.
What is nacre and why does it matter?
Nacre is the substance secreted by a mollusc to coat an irritant and form a pearl. It is composed of microscopic platelets of aragonite (calcium carbonate) bound by organic proteins, and its layered structure creates the distinctive lustre that makes pearls unique. Nacre thickness is a critical quality indicator: thicker nacre produces stronger lustre and a more durable pearl.
How can I tell if a pearl is real?
The most reliable at-home test is the tooth test: gently rub the pearl against your tooth. A real pearl feels slightly gritty due to its layered nacre structure; an imitation pearl feels smooth. Real pearls also feel cool initially, are heavier than plastic imitations, and show natural variation in their surface rather than the uniform artificial sheen of imitation pearls.
What should I look for when buying pearl jewellery?
Prioritise lustre above all other factors — it is the most visible indicator of pearl quality and the characteristic that most directly determines how beautiful a pearl looks in wear. After lustre, consider shape (round is rarest and most traditional; baroque is increasingly popular for contemporary designs), surface quality (minimal visible blemishes), and colour (personal preference, though evenness of colour and overtone are quality signals). Purchasing from a reputable jeweller with knowledgeable staff is the simplest assurance of authenticity and quality.
How should I care for pearl jewellery?
Always put pearls on last, after perfume and cosmetics. Wipe gently with a soft cloth after each wear. Avoid water, chemicals, and prolonged sunlight. Store pearl necklaces flat and separately from other jewellery. Have pearl strands professionally re-strung every one to three years. Visit our Jewellery Services at any Poh Heng boutique for professional care and re-stringing.