What is a Pearl?
Think of a pearl as a bandage for a mollusk. When a tiny foreign particle or parasite enters the shell of an oyster or mussel, some species secrete a substance called nacre to sooth the irritation and prevent infection. Nacre consists of calcium carbonate and protein. Over time, the nacre grows layer by layer into a beautiful, lustrous pearl.
In the gem world, pearls are unusual because they have an organic origin. Most gems have inorganic origins as minerals that form within the Earth.
Pearls can grow in a variety of mollusk species in both saltwater and freshwater. They can grow in both cold and warm water oceans as well as in rivers in almost every continent. However, pearl-producing mollusks are endangered in the wild. The vast majority of pearls on the market today are cultured. They come from underwater farms that grow them in mollusks under controlled conditions — from the moment irritants are artificially inserted into them to their harvest years later.
How Can You Tell Cultured from Natural Pearls?
Unless you’re explicitly told otherwise, assume any pearl you find for sale is cultured.
To check if a drilled pearl is cultured, examine its drill hole. Cultured pearls will have a thin layer of nacre covering an obvious white bead or “seed.” Wild pearls should have nacre nearly all the way through the pearl. However, some freshwater cultured pearls have virtually no seed except a bit of foreign mollusk tissue.
Undrilled pearls require an X-ray examination at a gemological lab to determine whether they’re cultured or natural.
Pearl Qualities and Engagement Ring Stones
Like diamonds and other gems, many factors contribute to the beauty and value of pearls. However, pearls are evaluated somewhat differently than other gems. Their most significant quality factors include luster, shape, surface, size, and color. A pearl lacking in any of these areas would have less value than a “well-rounded” pearl.
To learn more about these factors and how pearls are graded, consult our Pearl Buying Guide.
The paramount quality of pearls is luster. In fact, other gems are sometimes described as having “pearly luster” because their surfaces look like pearls when they reflect light.
Luster indicates how much brilliance and glow a pearl gives off. The brighter the pearl and sharper its reflection, the more beautiful and valuable. Typically, thicker nacre makes a pearl more lustrous. Although different types of pearls have different luster standards, never buy a pearl that appears dull or chalky.
Pearls can also exhibit orient, an iridescent display of rainbow colors. Orient generally makes a pearl more valuable.
Predicting or controlling the shapes of the pearls that mollusks produce proves extremely difficult. Most form baroque pearls, meaning pearls with irregular shapes. Round shapes are rarest, so the most valuable pearls are round.
Ideally, round pearls should be perfect spheres, not ovals, without dimples or rings. They should have even, all-around color and luster distribution. Most ring designs will cover the bottom part of a pearl, which fortunately might give budget-minded buyers a break. A round pearl with a blemish on just one side may cost less, and the ring setting could easily disguise or hide the blemish.
Pear or teardrop-shaped pearls are perhaps the most valuable type of baroque pearl. Flat, button pearls are inexpensive. However, baroque pearls rarely see ring use. So, adventurous buyers might commission a custom jeweler to incorporate a baroque pearl’s unique shape into a one-of-a-kind engagement ring setting, especially if the pearl has high luster, beautiful orient, and large size.
Closely related to shape, surface refers to the smoothness and cleanness of the pearl. Ideally, a pearl should have no dimples, scratches, or other irregularities. Irregularities that go all the way around a pearl, like a groove or ring, will affect both its shape and value.
The price of pearls increases exponentially with size. For a pearl engagement ring center stone, try to buy one 8 mm or larger. However, consider the other quality factors first and make the best choice you can afford.
Although pearls are popularly associated with the color white, they can occur in a wide range of colors, including black, gold, pink, lavender, peach, and silver. Their color depends on the type of mollusk that produces it as well as its environment.
Of course, choosing pearl color is a matter of personal preference, especially for an engagement ring. However, pearl colors do affect value. Generally, pure white, true black, and rich gold will command the highest prices. Peach and brown hues are less expensive. However, their popularity is gradually rising.
In addition to body color, pearls can also have overtones, colors that overlay the body color of a pearl. In general, overtone plays an important role in pearl value. For example, white pearls will hold greater value if they have pink, cream, or silver overtones. On the other hand, green or yellow overtones may lower their value.
Overtone as well as orient play vital roles in the beauty of black pearls. The best black pearls have several colors, such as pink, purple, or green, floating on top of their dark body color. They have an almost “soap bubble” iridescent effect. Other popular overtones for black pearls include silver and green.
Types of Pearls
There’s no way of telling what quality of pearl a certain mollusk will produce. The nacre of a particular pearl may or may not scatter light in just the right way to create both overtones and orient. This variability is part of what makes pearls so unique. Of course, types of pearls tend to have some characteristics in common. Gem lovers cherish each type of pearl for its unique combination of color, size, and luster.
Price per pearl estimates below are for cultured pearls.
Historically, freshwater pearls formed in nature all over the world. However, most freshwater pearls today are cultivated, and China is the world’s largest producer.
Freshwater pearls have the widest color range. These include white, cream, yellow, orange, pink, and purple as well as potential overtones of pink, green, or blue. The only color they don’t produce naturally is black. Therefore, rest assured any black freshwater pearls you encounter for sale are certainly dyed. Unfortunately, such pearls always appear dull and artificial. Freshwater pearls vary from 4 to 14 mm in size and can have bright luster.
Since freshwater pearls are easily mass cultivated, they rank as the most affordable type of pearl. A single freshwater mussel or oyster may produce numerous pearls. In the past, these mollusks yielded mostly off-round pearls. Improvements in pearl farming now ensure the availability of large, round freshwater pearls.
If you’re shopping for a pearl engagement ring stone on a budget, freshwater cultivated pearls make an excellent choice. They may cost anywhere from a few dollars up to $200 per pearl, depending on size and quality. High-quality freshwater pearls are nearly indistinguishable from Akoya pearls.
The ideal of the white, round pearl originated with saltwater pearls. However, the seas can yield amazing variations, too.
If you were to ask people to imagine a classic strand of pearls, most would likely visualize white Akoya pearls with silver overtones. Grown in the cooler waters around Japan and China, renowned Akoya pearls have incredible roundness, mirror-like shine, and sharp reflections. They have the highest luster of any pearl type because they grow more slowly due to their cold-water environment. They can have white, cream, yellow, pink or blue body colors with pink, silver, or green overtones.
Akoyas tend towards smaller sizes, ranging from 2-11 mm but typically falling within the 6-8 mm range. As a result, size ranks as the greatest determiner of an Akoya’s value. As it grows in size, so does its price. Because of their relative smallness, Akoyas are most often worn as pearl strands. (6-8 mm still makes a good size for a center stone).
Akoya prices per pearl can range from $30 to $300, depending on size and quality.
Tahitian pearls grow off of Tahiti and other French Polynesian islands. They’re the only type of pearl that occurs naturally in black, so they’re also sometimes referred to as black pearls. However, their color palette covers black, gray, brown, blue, green, and purple. They’re also valued for colorful overtones of pink, green, or blue that accent their dark body colors. Tahitian pearls range in size from 9-14 mm, with an average of 9.5 mm.
Grayish purple Tahitian pearls are known as aubergine pearls because of their “eggplant” color. Greenish yellow or yellowish green Tahitian pearls are known as pistachio pearls. Peacock pearls, the most highly valued Tahitian pearls, have dark green to blue-gray colors with rose to purple overtones.
Tahitian prices per pearl can range from $75 to $450, depending on size and quality.
South Sea Pearls
South Sea pearls are cultivated in the warmer waters off the coast of Australia and the Philippines. The largest and most expensive type of pearl, they range in size from 8-20 mm, averaging 13 mm. Due to their size, jewelers often use them as center stones.
South Sea pearl colors include white, cream, silver, yellow, orangey yellow, and blue with pink, green, or blue overtones. South Sea oysters are especially known for producing high-quality golden pearls. Only their pearls can achieve that rich, saturated orangey yellow color. However, South Sea pearls often have less brilliant luster than other pearls. Instead, they tend to show a mellower, satiny glow often described as “creamy.” Although a South Sea pearl should still have wonderful shine, its reflections may appear more diffused than an Akoya’s, for example.
Golden South Sea pearls can show champagne, rose, or green overtones, but purely golden pearls have more value.
South Sea prices per pearl can range from $120 to $650, depending on size and quality.
Tips for Pearl Engagement Ring Stones
Drilled or Undrilled?
If you buy undrilled pearls, you’ll have greater flexibility when choosing a jewelry design. Since holes can be used to remove minor blemishes, usually only lower quality pearls are sold drilled and in strands. The highest quality pearls are sold loose and undrilled. Of course, undrilled pearls cost more than drilled pearls.
Like many gemstones, pearls can receive many kinds of treatments or enhancements. Some may significantly improve the visual appeal of a pearl, while others may wear off or have unintended and unsightly consequences.
Freshwater pearls are sometimes dyed to create a wide variety of colors. Typically, manufacturers do this to lower quality pearls. Dyed pearls will look artificial unless the dyed color is very light. You can easily detect dye because it concentrates around drill holes.
Freshwater and Akoya pearls are sometimes exposed to silver nitrate or gamma rays to turn them blue-gray or black. In freshwater pearls, the nacre darkens, making the pearl look metallic. In Akoya pearls, only the bead darkens, giving the pearl a bluish cast.
Gamma rays don’t always create stable colors in pearls. In addition, treated freshwater pearls in particular will take on an unnatural metallic sheen.
Imitation, faux, or fake pearls are pieces created to simulate or look like real pearls. You’ll often find plastic or glass pieces coated in opalescent paint as imitations of pearls.
The telltale sign of a fake is that it’s simply too perfect. All pearls, except for those of the highest quality, will have minute surface irregularities. Under a loupe or microscope, cultured pearls will appear to have translucent rippled layers stacked on top of one another. You can see this most easily with a strong light source to the side of the pearl. Those rippled layers are natural layers of nacre.
Some merchants will also rub pearls against one another or against their teeth lightly. If the texture feels gritty, the pearl is genuine. If the texture is completely smooth, the item is most likely an imitation. However, rubbing pearls too hard against other pearls or your teeth can damage them.
Cultured Pearls are Not Fakes
Please keep in mind that cultured pearls are real pearls but not natural pearls. Cultured pearls are produced by living organisms in the same manner as in nature, only under human supervision. While natural pearls command much greater value and prestige, both natural and cultured pearls are structurally essentially lustrous balls of nacre. Cultured pearls aren’t fake pearls.
However, selling cultured pearls as natural pearls (at natural prices) is a dishonest practice. Buyer beware. Again, most pearls on the market today are cultured.
Caring for Your Pearl Engagement Ring
Of all the most popular gemstones, pearls are the softest. They have a very low Mohs hardness of 2.5-4.5, which measures resistance to scratching. A pearl isn’t much harder than a fingernail, so it will scratch very easily. These gems also have extreme sensitivity to heat and chemicals. Since pearls consist of calcium carbonate, even mild acids can damage them.
So setting, wearing, and storing your pearls require special attention.
Setting Your Pearl Engagement Ring Stone
Jewelers generally set pearls by drilling on one or both ends. For a pearl, the ring setting usually sports a needle coated with glue, which the jeweler inserts into the drill hole. When the glue dries, the pearl should be stable and neither spin nor fall out. Typical prong settings like those used for other gems may allow a pearl to spin, which will scratch it. Thus, pearls are sometimes glued onto prongs.
It’s difficult for any ring setting to protect a pearl, unless the pearl is set low into a flower or bowl design. Some pendant designs house pearls in a protective metal cage, which might translate into a creative ring setting.
Since roundness and luster characterize pearls, many jewelers (and consumers) will try to accentuate these qualities. For most ring settings, that means sitting the pearl high up in the ring. The only way to protect the pearl in such a dramatic setting is to be especially careful when wearing it.
Wearing and Storing Your Pearls
Keep all household cleaners and cosmetics away from your pearls.
Follow this general rule for wearing any pearl jewelry: “Last thing on, first thing off.” This will keep makeup and perfume from dulling your pearls. Over time, even sweat can dull pearls, so wipe them off carefully after wearing them. Store your pearls in a soft cloth bag away from heat sources. Heat can cause pearls to crack and discolor.
You should also store your pearls where moisture in the air will keep them from dehydrating and losing color. Don’t keep pearls in enclosed spaces like safes for long periods of time.
Cleaning Your Pearl Jewelry
All pearls requires extra care when cleaning. See our special guide for cleaning pearls and opals.
Here are some basic rules:
- Never clean your pearls in mechanical cleaning systems, like ultrasonic or steam systems, and never boil them.
- Use only warm water, mild soap, and a soft brush (not a toothbrush) to clean your pearls.
- If you have drilled pearls, don’t soak them in soapy water. This may cause moisture to build up in the holes.
- Dry your pearls by patting and daubing them carefully with a lint-free cloth only.
For more recommendations, consult our gemstone jewelry cleaning guide.
Style Choices for Your Pearl Engagement Ring
You can incorporate pearls into engagement rings in many styles, from vintage to classic to modern.
Vintage rings often use smaller pearls set in a diamond-shaped cluster of two or four, surrounded by diamond accents, vine motifs, or milgrain. This style can inspire some attractive and affordable pieces, since smaller pearls cost less. Eternity band designs also utilize smaller pearls, with pearls either all around or interspersed with diamonds or milgrain. (Pearl eternity bands look great in both vintage and modern styles, too).
Classic pearl rings consist of a large center pearl surrounded by a diamond halo, diamond accents, or floral motifs. These rings tend towards simplicity, accenting the smoothness and luster of the center gem.
Modern pearl rings include open rings with large pearls on either side of pearls clustered together to look like bubbles. Some modern designers especially love Tahitian pearls and pair them with simple white gold bands for a clean, sleek look.
Other designers create more intricate looks. London-based jewelry designer Sarah Ho created a beautiful pink pearl ring surrounded by diamond petals. Some designers facet their pearls, giving the pearls a unique, convex golf ball-like appearance.