Pearl: June's Original Birthstone and the Only Gem Born from a Living Creature

Pearl is June's original birthstone and the only gem grown rather than mined. Five types matter most for collectors: Akoya ($100 to $1,000), Tahitian ($200 to $2,000), South Sea ($500 to $10,000 and above), Freshwater including Edison ($50 to $500), and rare natural pearls. Luster is the single most important quality factor, followed by surface, shape, size, color, and nacre thickness. Pearls rate 2.5 to 4.5 on the Mohs scale and need gentle care.

Pearl is June's original birthstone, and it holds that distinction for good reason. Long before the American National Retail Jewelers Association formalized the modern birthstone list in 1912, pearls were already the gem most closely associated with the month of June. Ancient cultures linked pearls to the Moon, to tears of the gods, to purity and wisdom. That connection runs so deep that even after alexandrite and moonstone were added as alternate June birthstones, pearl remains the one most people reach for. It is also the only gemstone created by a living organism, which gives it a fundamentally different character from every other stone on the birthstone chart. Every other birthstone is mined from the earth. Pearl is grown inside a mollusk, layer by patient layer, over months or years.

I have been sourcing pearls for over a decade now, from the massive Tucson Gem Show to dealer showrooms in Las Vegas and workshops in Jaipur, India, where my master artisans set pearls alongside colored gemstones. What draws me to pearls is that no two are truly alike. A fine South Sea pearl has a glow that seems to come from somewhere deep inside the gem itself, a warmth that diamonds and faceted stones simply cannot replicate. Whether you are shopping for your first pearl necklace or adding a rare golden South Sea pendant to an established collection, understanding how pearls form, how they differ, and how to evaluate quality will make you a more confident buyer. That is exactly what this guide is for.

How Pearls Form: Nature's Only Living Gemstone

A pearl begins when an irritant, a tiny particle of shell, a grain of sand, or in cultured pearls a carefully placed bead nucleus, enters the soft tissue of a mollusk. The mollusk responds by coating the irritant with nacre, a composite material made of aragonite crystals (a form of calcium carbonate) and conchiolin (an organic protein that acts as a binding agent). Nacre is the same iridescent material that lines the inside of the shell, which is why the interior of an oyster or mussel gleams with that characteristic pearly sheen. The mollusk deposits nacre in thousands of thin, overlapping layers, and it is the way light refracts through those translucent layers that creates the deep luster we associate with fine pearls.

Natural pearls form entirely without human intervention. A wild mollusk encounters an irritant by chance, and the pearl that results is entirely a product of nature. Genuine natural pearls are extraordinarily rare. Most natural pearls on the market today are vintage or antique pieces, and they command exceptional prices at auction. The vast majority of pearls available to modern buyers are cultured pearls, which are created by intentionally introducing a nucleus into the mollusk under controlled conditions. The culturing process was perfected by Kokichi Mikimoto in Japan in the early 1900s. Mikimoto spent years developing a reliable method for producing round, lustrous pearls, and his work revolutionized the pearl industry by making these gems accessible to a far broader audience. Cultured pearls are natural pearls. The mollusk produces nacre the same way it would for a natural pearl. The only difference is that a human started the process rather than leaving it to chance.

The time a pearl spends inside the mollusk matters enormously. Akoya pearls typically culture for 10 to 18 months. South Sea and Tahitian pearls may remain in the oyster for two to four years. Longer culturing periods generally produce thicker nacre, and thicker nacre produces richer luster and greater durability. According to the Gemological Institute of America, nacre thickness is one of the seven core quality factors that separate a truly fine pearl from a mass-produced one.

Pearl Types Every Collector Should Know

Not all pearls are created equal, and understanding the major types is the single most useful thing a buyer can learn. Each type has distinct characteristics, a different price range, and a different personality. Here are the five categories that matter most.

Akoya Pearls

Akoya pearls are the classic white pearl that most people picture when they hear the word "pearl." Produced primarily in Japan and China using the Pinctada fucata oyster, Akoya pearls are renowned for their near-perfect round shapes and exceptionally sharp, mirror-like luster. They typically range from 6 to 8mm in diameter, though sizes up to 9 or even 10mm exist and are considerably more valuable. The body color is usually white or cream, often with a rose or silver overtone that adds depth and warmth. Akoya strands remain the gold standard for pearl necklaces, and a well-matched Akoya strand with fine luster is one of the most elegant pieces of jewelry you can own. Japan's cold waters produce a particularly bright, sharp luster that distinguishes the best Akoya pearls from their Chinese-grown counterparts. Retail prices for Akoya strands typically run from $100 for entry-level pieces to $1,000 and beyond for top-grade, well-matched strands.

South Sea Pearls

South Sea pearls are the largest cultured pearls in the world, typically ranging from 9 to 16mm and occasionally exceeding 20mm. They are produced by the Pinctada maxima oyster in the warm waters of Australia, Indonesia, and the Philippines. South Sea pearls come in two main varieties: white and silver tones from Australian waters, and golden tones from the Philippines and Indonesia. Golden South Sea pearls are among the most coveted pearls on the market today, and their rich, saturated color is entirely natural, not treated or dyed. The nacre on South Sea pearls is exceptionally thick because these oysters culture for two to four years, which gives the pearls a distinctive satiny luster that is softer and more luminous than the sharp mirror finish of an Akoya. Size, combined with rarity and the time required to produce them, makes South Sea pearls among the most expensive cultured pearls available, with prices ranging from $500 for smaller individual pearls to $10,000 and well above for fine matched strands of large golden South Sea.

Tahitian Pearls

Tahitian pearls are the only naturally dark pearls in the world. Produced by the Pinctada margaritifera oyster in the lagoons of French Polynesia, they are often called "black pearls," but that name barely scratches the surface. Tahitian pearls display an extraordinary range of colors: charcoal gray, forest green, deep aubergine (eggplant), peacock (a blend of green, purple, and gold), and everything in between. The most prized color is peacock, where multiple overtones shimmer across the surface of a dark-bodied pearl. Tahitian pearls typically range from 8 to 14mm and have a rich, complex beauty that makes them ideal for bold, modern jewelry. They bring an edge and sophistication that lighter pearls do not, and they look particularly striking against warm skin tones. Retail prices generally run from $200 for smaller individual Tahitians to $2,000 and beyond for fine peacock strands.

Freshwater Pearls

Freshwater pearls are produced primarily in China using various species of freshwater mussels. They are the most affordable pearl type, which makes them an excellent entry point for new collectors and a versatile option for everyday jewelry. Freshwater pearls come in a wide range of shapes, sizes, and natural colors, including white, pink, peach, and lavender. Historically, freshwater pearls were known for irregular shapes and lower luster compared to saltwater varieties, but quality has improved dramatically in recent decades. Edison pearls, a newer freshwater variety, produce large (12 to 16mm), round, high-luster pearls with rich metallic overtones that rival saltwater quality at a fraction of the price. Metallic freshwater pearls with intense rose, bronze, or rainbow overtones have become collector favorites in their own right. If someone told me ten years ago that freshwater pearls would be competing with South Sea quality, I would have been skeptical, but the best Edison pearls have changed the game entirely. Typical retail pricing runs from $50 for simple freshwater pieces to $500 and beyond for fine Edison strands.

Natural Pearls

Natural pearls form without any human intervention. A wild mollusk encounters an irritant by chance and produces a pearl entirely on its own. Because pearl farming has made cultured pearls abundant, natural pearls are extraordinarily rare today. Most natural pearls available on the market are vintage or antique, passed down through estates and collections. Natural pearls are identified through X-ray analysis, which reveals their concentric layered structure (as opposed to the bead nucleus visible in most cultured pearls). At auction, natural pearl strands and individual specimens can sell for hundreds of thousands or even millions of dollars. For most buyers, cultured pearls are the practical choice, but understanding natural pearls helps you appreciate the history and rarity that made these gems so precious in the first place.

Evaluating Pearl Quality

Unlike diamonds, pearls do not have a single universal grading system. Different dealers and organizations use different letter-grade scales. However, the fundamental quality factors are consistent across the industry, and understanding them will help you evaluate any pearl you encounter, regardless of the grading terminology used. The International Gem Society publishes a clear breakdown of the seven core factors used by professional graders.

Luster

Luster is the single most important quality factor in a pearl. It refers to the sharpness and intensity of the light reflected from the pearl's surface, as well as the glow that seems to emanate from within. A pearl with excellent luster will show crisp, bright reflections. On a top-quality Akoya pearl, you should be able to see your own reflection on the surface, almost like a tiny convex mirror. Dull, chalky, or waxy luster is a clear sign of lower quality and usually indicates thin nacre. When you are comparing pearls, luster should be the first thing you evaluate, even before size or shape.

Surface Quality

Perfectly clean, blemish-free pearls are rare in any type. Most pearls have some surface characteristics: tiny spots, bumps, wrinkles, or indentations. Minor blemishes are normal and can even help confirm that a pearl is genuine rather than imitation. However, heavy spotting, deep pitting, cracks, or large blemishes that are visible to the naked eye will reduce the pearl's value. The key is whether the blemishes are noticeable at a conversational distance (about arm's length) or only visible under close magnification. A pearl that appears clean at arm's length is considered high quality, even if a loupe reveals minor imperfections.

Shape

Perfectly round pearls are the most valued for strands and matched sets, because achieving a well-matched round strand requires selecting from thousands of individual pearls. However, shape preference is partly a matter of personal taste and intended use. Drop-shaped pearls are highly prized for earrings and pendants because they hang beautifully. Baroque pearls, with their freeform irregular shapes, have a sculptural quality that appeals to designers and collectors who appreciate organic forms. Some of the most striking pearl jewelry I have seen uses large baroque pearls as one-of-a-kind statement pieces.

Size

Larger pearls are rarer and more valuable, all other quality factors being equal. Akoya pearls over 9mm are uncommon and expensive. South Sea pearls over 15mm command significant premiums. Size is measured in millimeters, and even a 1mm difference can represent a meaningful jump in price, particularly at the larger end of the range. Keep in mind that size alone does not determine value. A smaller pearl with exceptional luster will often be more beautiful, and more valuable, than a larger pearl with dull luster and heavy blemishes.

Color

Pearl color has three components: body color (the dominant overall color), overtone (a translucent secondary color that appears to float over the surface), and orient (a rainbow iridescence visible on some pearls). The most classic combination is a white body with rose overtone, which has been the standard for Akoya strands for generations. Peacock overtone on Tahitian pearls, where green and purple shimmer across a dark gray body, is one of the most coveted colors in the pearl world. Golden South Sea pearls with deep, saturated color are increasingly popular and command top prices. Color preference is largely personal, but certain combinations are rarer and therefore more valuable in the market.

Nacre Thickness

Nacre thickness directly affects both luster and durability. Thicker nacre produces richer luster because light has more layers to refract through, creating that deep inner glow. It also means the pearl will last longer and resist wear. Cheap, mass-produced pearls with very thin nacre may look acceptable when new but will peel, chip, or develop a chalky appearance over time as the thin nacre wears through to the bead nucleus beneath. This is one of the most important reasons to buy from reputable sources. A pearl with thick, high-quality nacre is an investment that will look beautiful for decades. A pearl with paper-thin nacre is a disappointment waiting to happen.

Pearl Style Archetypes in the Ulka Rocks Collection

One of the easiest ways to choose a pearl piece is to start from the role it will play in your wardrobe. The Pearl Collection at Ulka Rocks spans three clear archetypes, each built from a different pearl type and price tier, and each curated at trade shows including the Tucson Gem Show and JCK Las Vegas. Use the table below to find the tier that matches your goal.

Across the live Pearl Collection, the entry tier is anchored by mother-of-pearl pendants and freshwater bracelets that start near $70, the statement tier is built around 30 inch and 35 inch Tahitian, Edison, and Keshi pearl strands knotted with diamond clasps, and the heirloom tier includes pieces such as the 18k white gold pearl combo at $9,800 and the 14k yellow gold pearl ring at $2,550. Pieces are sourced directly by Ulka from dealers in Tucson, Las Vegas, and Jaipur, India.

Pearl History and Cultural Significance

Pearls may have the longest history of any gemstone used in jewelry. The oldest known pearl jewelry dates to approximately 520 BC, discovered in the sarcophagus of a Persian princess. Unlike colored gemstones that required cutting and polishing technology to reveal their beauty, pearls emerge from the mollusk ready to wear. This made them among the first gems to be valued by human civilizations.

In ancient Rome, pearls were the ultimate symbol of wealth and status. Roman women adorned themselves with pearl earrings, necklaces, and bracelets, and the gem was so associated with luxury that Julius Caesar passed a law restricting pearl wearing to the ruling classes. Pliny the Elder described pearls as the most valuable of all gems. The most famous pearl story from antiquity involves Cleopatra and her legendary bet with Marc Antony. According to the account, Cleopatra wagered that she could spend ten million sesterces on a single banquet. She dissolved one of her enormous pearl earrings in a cup of vinegar and drank it, winning the bet in spectacular fashion. Whether the chemistry of that story holds up to scrutiny is debatable, but the legend itself tells us how Romans and Egyptians viewed pearls: as gems of incomparable worth.

In Hindu tradition, pearls are associated with the Moon and are believed to bring calmness, purity, and emotional balance. Hindu texts describe pearls as one of the nine sacred gems (Navaratna), and they have been integral to Indian jewelry for thousands of years. My artisans in Jaipur work with pearls in ways that connect directly to this tradition, setting them alongside rubies, emeralds, and sapphires in designs that echo centuries of Indian craftsmanship.

One of history's most famous individual pearls is La Peregrina, a large, pear-shaped natural pearl discovered in the Gulf of Panama in the 16th century. It passed through the royal houses of Spain, France, and England before being purchased at auction by actor Richard Burton as a gift for Elizabeth Taylor in 1969. Taylor had it set in a Cartier necklace featuring diamonds and rubies, and when her collection was sold at auction in 2011, La Peregrina sold for over $11 million. The journey of that single pearl, from a Panamanian oyster to a Spanish queen to one of Hollywood's most famous women, captures the timeless fascination pearls hold across cultures and centuries.

The history of birthstones traces pearl's association with June back through centuries of tradition, well before any formal list was established.

Styling Pearl Jewelry

If your image of pearl jewelry is limited to a single strand of matched white pearls, it is time for an update. Modern pearl jewelry has expanded in every direction: asymmetric designs, mixed-metal settings, baroque pearl pendants on chunky gold chains, layered strands mixing different pearl types and sizes, and minimalist single-pearl pieces that work with everything from a blazer to a T-shirt.

White Akoya strands remain timeless for formal occasions: weddings, galas, professional settings where understated elegance is the goal. A 7mm or 7.5mm Akoya strand with fine luster is arguably the most versatile piece of fine jewelry a woman can own. Tahitian pearls bring edge and modernity. A single dark peacock pearl pendant on a simple chain adds instant sophistication to a date-night outfit or a sharp business look. Golden South Sea pearls have a warm richness that complements both gold and rose gold metals beautifully. Freshwater pearls offer the most versatility at the most accessible price points. A pair of pink freshwater pearl studs, a layered baroque pearl necklace, or a modern pearl and chain bracelet are all options that work across occasions and wardrobes.

One trend I love is the mixing of pearl types in a single piece or a layered look. Combining a short Akoya choker with a longer Tahitian or South Sea necklace creates visual interest and depth. Mixing pearl sizes, from tiny seed pearls to large baroque shapes, adds texture and personality. Pearls also pair beautifully with colored gemstones. I have seen stunning combinations of pearls with moonstone, turquoise, sapphire, and even raw diamonds. The soft, organic quality of a pearl provides a gorgeous contrast to the sharp facets of a cut stone.

For more ideas on how pearls fit into modern jewelry wardrobes, read our in-depth guide to extraordinary pearls.

Caring for Pearl Jewelry

Pearls are organic gems and require more careful handling than most other jewelry. On the Mohs hardness scale, pearls rate between 2.5 and 4.5, which makes them significantly softer than virtually every other gemstone in your collection. That softness is part of what gives pearls their beautiful luster, but it also means they are vulnerable to scratching, chemical damage, and dehydration.

Here are the essential care guidelines every pearl owner should follow:

Avoid chemicals. Perfume, hairspray, lotion, sunscreen, and household cleaning products can all damage nacre over time. The acids and alcohols in these products dull the luster and can erode the nacre surface. Put your pearls on after you have finished applying cosmetics, fragrances, and hair products.

Wipe after wearing. After each wear, gently wipe your pearls with a soft, slightly damp cloth. This removes body oils, perspiration, and any residue that may have accumulated during the day. Do not use soap, detergent, or any cleaning solution. Plain water on a soft cloth is all you need.

Store separately. Pearls should be stored away from harder gems and metals that can scratch their soft surface. Wrap them in a soft cloth or keep them in a separate compartment of your jewelry box. Avoid airtight containers or plastic bags, as pearls need a small amount of moisture in the air to prevent the nacre from drying out and cracking. A fabric-lined jewelry box in a room with normal humidity is ideal.

Restring regularly. If you wear a pearl necklace or bracelet regularly, have it restrung every one to two years. Pearl strands are typically strung on silk thread with knots between each pearl. The silk stretches and weakens over time, and the knots can accumulate dirt. Restringing keeps the strand secure and maintains its appearance. Knotting between each pearl also prevents the pearls from rubbing against each other and protects them if the strand breaks.

Never use ultrasonic cleaners or steamers. These cleaning methods, which are perfectly safe for diamonds and many colored gemstones, can crack or destroy pearl nacre. Pearl cleaning should always be done by hand with a soft cloth.

Wear them. This may seem counterintuitive given all the care instructions, but pearls actually benefit from being worn. The natural oils from your skin help keep the nacre hydrated and maintain its luster. Pearls that sit in a box for years without being worn can dry out and become dull. The best thing for your pearls is to enjoy them regularly, just treat them gently.