Discover everything about pearl value, types, and care in our comprehensive guide. Learn to evaluate pearl quality, understand differences between natural and cultured pearls, and maintain your pearl jewelry properly.
13 Minute Read
In this in-depth article, you'll discover:
Pearls rank among our most ancient gemstone materials, treasured in jewelry for approximately 6,000 years. Historical records document commercial pearl harvesting dating back at least 2,500 years. The cultivation of "blister pearls" began in China as early as the 13th century CE, demonstrating humanity's long fascination with these organic gems.
While oysters remain the best-known pearl producers, various mollusks including clams, mussels, and abalone can create pearls. Today, truly natural pearls exist as extraordinary rarities. In wild populations, only one in several million mollusks will ever produce a pearl. This extreme scarcity explains why cultured or farm-grown pearls dominate today's market.
A pearl forms when an irritant penetrates deeply enough into a mollusk's shell that the creature cannot expel it. The mollusk's shell-producing system responds by coating the irritant with nacre, the lustrous substance lining most shells. Nacre consists of the mineral aragonite combined with an organic binder called conchiolin. The thin nacre layers create a diffraction grating through which light passes, producing a pearl's distinctive luster.
Natural pearls nearly vanished from the market in the late 1800s due to overharvesting. Even today, they remain extremely rare and command extraordinary prices. As natural sources became depleted, the modern era of cultured pearl production began in Japan around 1910. "Perliculture" or pearl farming enables producers to create pearls in greater quantities and larger sizes than would naturally occur.
Despite the addition of alexandrite to modern lists, pearls remain the gemstone most commonly recognized as the June birthstone. Pearls also maintain a strong connection to weddings and, in particular, brides. This association isn't merely clever modern marketing—pearls have symbolized weddings, fertility, and love for thousands of years across many cultures.
For more information on pearl symbolism, see our article on its legends and lore.
The surface iridescence on orient of pearls results from diffraction at the edges of overlapping aragonite crystal plates. These edges also cause the roughness detected in a "Tooth Test." Every pearl displays both a body color and "overtones" of rainbow hues created by this admired phenomenal effect.
Black pearls derive their dramatic coloration from a layer of dark conchiolin showing through the nacre. Their body colors include true black, gray, bronze, dark blue, blue-green, and green. Some specimens display striking metallic overtones. See our article on Tahitian and other black pearls for additional information.
Colored pearls display a pronounced body color—any hue except black or white. The most common body colors include blue pearl varieties, red, purple, violet, yellowish, and green. Typically, colored pearls feature a blue background color. These diverse colors appear more frequently in freshwater pearls than in saltwater varieties.
Darker pearl colors apparently result from dark conchiolin in the pearl's core showing through the thin layers of aragonite crystals.
The fluorescence of natural pearls ranges from inert to strong light blue, yellowish, greenish, or pinkish in both longwave (LW) and shortwave (SW) ultraviolet (UV) light. Cultured pearls may show no reaction or exhibit the same reaction as natural pearls under LW. Freshwater pearls consistently glow yellowish-white when exposed to X-rays.
Natural black pearls may display weak to moderate red, orangish red, or brownish red fluorescence under LW. Dyed black pearls may show variable reactions under LW but never match the fluorescence patterns of natural black pearls.
La Paz pearls exhibit a distinctive strong red reaction under LW UV light.
Cultured pearls represent the pearl equivalent of synthetic gems. Cultured pearls form under the same conditions as their natural counterparts and share identical chemical and physical properties, with a few revealing differences. Unlike laboratory-created gems, however, cultured pearls grow in both saltwater and freshwater farms.
Akoya pearls represent the most well-known and highly prized type of cultured pearl on today's market.
In underwater pearl farms, cultivators carefully insert pieces of mantle tissue and mother-of-pearl seeds or shell beads into bivalve mollusks such as oysters. The animals secrete nacre to coat these irritants, just as they would naturally respond. The composition and structure of this nacre remains essentially identical to naturally-formed nacre.
After this surgical intervention, the oysters convalesce in a "hospital" environment for four to six weeks. Workers then transfer them to cages positioned seven to ten feet underwater. Here, they continue developing for one to six years. The cultivation period varies depending on farm conditions, mollusk species, and the desired pearl characteristics.
In this video, Jake Talve-Goodman of The Concierge Gemologist explains the differences between saltwater and freshwater pearl cultivation techniques. These pearls also typically find different uses in jewelry. Please note: marine mollusks can produce multiple cultured pearls at a time, but these are smaller than single-yield pearls.
Some cultured pearls can be distinguished from natural pearls through X-ray examination at a gemological laboratory. This technique can reveal the seed used to initiate nacre layer formation. You might also spot the seed if a pearl has a drill hole, so use judgment before requesting X-ray testing. Identifying certain cultured pearl types requires more advanced gemological testing methods.
Faux or fake pearls are pearl simulants. While cultured pearls constitute real pearls, simulants aren't pearls at all. Various materials including glass, shell, and plastic can mimic a pearl's luster through surface treatments. Faux pearls have existed for centuries, but with cultured pearl prices at historic lows, there's little incentive to purchase or wear imitations.
To determine whether a pearl is genuine or fake, try the simple "Tooth Test." Gently rub the pearl across your teeth's surface. Genuine pearls will feel slightly gritty or rough, while most imitations feel completely smooth.
Various treatments can change the color of pearls.
The most crucial factor when evaluating a pearl's value is determining whether it's natural or cultured. Contrary to popular belief, whether it's a saltwater or freshwater pearl doesn't affect its value. Natural pearls command significantly higher prices than cultured varieties due to their extreme rarity.
Experts grade all pearls—whether natural or cultured—based on several key factors: luster, nacre thickness, shape, surface quality, color, and size. These properties determine a pearl's overall quality and value. For more detailed guidance on how to assess pearl value, consult our pearl buying guide and cultured pearl appraisal guide.
The more light a pearl's surface reflects and the sharper those reflections appear, the higher its luster. Very high or high luster indicates bright, sharp reflections. Soft or dull luster means the reflections appear weak, fuzzy, and diffused.
The thickness of a pearl's nacre layers affects its durability and directly relates to its orient and luster. Professional gemologists consider 0.25 to 0.35 mm good commercial grade, while 0.35 to 0.5 mm represents gem grade. Unfortunately, cultivation challenges often lead to faster harvests, affecting nacre thickness. Consequently, the highest grades now typically max out around 0.4 mm.
While measuring nacre isn't always feasible, you can gauge its thickness by assessing a pearl's luster and orient quality.
The closer a pearl approaches perfect roundness, the higher its value. Symmetry represents a secondary value factor. Typically, an oval pearl commands more value than a baroque shape.
Round pearls form almost perfect spheres with less than 2% variation in diameter. To determine whether a pearl is truly round, professional testers roll it across a table. If it rolls straight, it's classified as round. If the pearl veers off more than slightly, experts consider it semi-round. Semi-round pearls (also called off-round or near-round) represent slightly imperfect spheres. Their diameter variation falls between 2% and 5%.
Ringed or circled pearls display regular streaks, rings, or grooves. These markings must appear perpendicular to the rotation axis and cover more than one-third of the surface area.
Baroque pearls exhibit irregularity in every direction without any rotation axis. Semi-baroque pearls, however, display at least one rotation axis, allowing them to spin on one end like a top. Baroque subdivisions include drop, button, pear, and oval shapes.
Surface grading is done with the naked eye rather than a loupe. Two principal factors influence the surface grade: the size or texture of the surface irregularities and how much surface area they cover.
The Tahitian pearl grading system uses the following grades. However, the principles apply to all pearls.
When grading pearl colors, experts must consider body color and overtone simultaneously. Not all pearls display overtones, and those that do show tremendous variation.
For light pearls, body color values progress from white to silver, then cream, and finally into increasingly yellow shades. With orient present, top values belong to light rose pearls (white body color with pink overtones). Next come cream rose pearls, featuring cream body color with deep rose overtone.
The most valuable fancy pearls display cream body colors with rose overtone plus green or blue secondary overtones.
For black pearls, darker colors closer to true black command higher values. Top-grade black pearls feature a green overtone called "peacock green." Multiple overtone colors rank next in value.
See our specialized guides to freshwater pearls and saltwater pearls for comprehensive information on pearl-producing mollusk species plus natural and cultivation sources worldwide.
Gemologists measure pearls in millimeters, grains, and mommes. One jeweler's grain equals 0.25 carats. A momme represents a quantity measurement for pearls, with one momme equaling 75 jeweler's grains or 18.75 carats. (Note that "grain" carries different values in other measurement systems).
Experts measure round and off-round pearls by their shortest diameter. Pearls in other shapes require measurement along their longest and second-longest dimensions.
As with any gemstone, larger specimens occur less frequently, commanding higher prices per weight unit. Round pearls typically range from 2 to 9 mm in diameter. Baroque pearls can reach impressive sizes up to 50 mm.
For information about large and famous named pearls, see our listings for freshwater and saltwater pearls as well as our article on seven famous pearls.
Pearls develop in symmetrical round and pear shapes. Jewelers refer to squat pear shapes as egg shapes, while elongated pear shapes become drop shapes.
The industry generally names pearls after their distinctive shapes. Beyond rounds and drops, you might encounter stick pearls, button pearls, seed or rice pearls, and many other shape-based classifications.
Baroque refers to any irregularly shaped pearl. These unique pearls carry many different trade names. Although symmetrical spheres remain the most popular and traditional pearl shape, the unusual forms baroques can assume often inspire truly unique jewelry designs.
Note how the baroque pearl's irregular shape captures the form of a torso from both front and back. Pendant in the form of a siren, baroque pearl with enameled gold mounts set with rubies. Probably ca. 1860, European, height 10.6 cm. The Jack and Belle Linsky Collection, 1982. Metropolitan Museum of Art, New York. Public Domain. (Cropped to show detail).
The trade classifies baroque pearls with poor luster as "slugs."
Sometimes jewelers use the term "keshi" to describe almost any baroque pearl. However, strictly speaking, this term refers to all-nacre, non-nucleated pearls that form spontaneously during South Sea pearls cultivation, as well as pearls intentionally nucleated with mantle pieces. See our article on keshi pearls for more information.
"Bombay" describes pearls with cream body color featuring rose overtone.
"Ceylon" or "Madras" refers to white or cream pearls displaying fancy overtones of green, blue, or purple.
La Paz pearls originate from coastal waters off Baja California, Mexico.
Today, the term "Oriental" applies exclusively to natural pearls from the Persian Gulf. Historically, this term referenced any pearls of saltwater origin.
Many gem materials have been called pearls due to their appearance and watery origins. Some of these materials are now referred to as calcareous concretions or non-nacreous pearls. They aren't true pearls, despite their names. Some well-known examples of calcareous concretions include conch pearls and tridacna pearls.
So-called blister pearls develop attached to the inside of a mollusk's shell. These dome-shaped, hollow pieces aren't true pearls.
Some artisans create mabe pearls by filling blister pearls and gluing them to a shell backing.
Other "pearls" in name only include the following:
Mother of pearl consists of the iridescent inner nacre layer found in most seashells—it isn't a pearl type. Skilled artisans can transform mother of pearl into beautiful jewelry and decorative objects.
Jake Talve-Goodman of The Concierge Gemologist introduces viewers to the fascinating world of mother of pearl and discusses its formation, sourcing, valuation, symbolism, and jewelry and decorative use.
Although pearls are delicate, jewelry makers have successfully made wonderful pieces from them for thousands of years. Nevertheless, if you want to enjoy your pearl jewelry for even a fraction of that time, you should exercise some caution. Along with opals, pearls merit their own detailed care guide.
Here are some basic guidelines:
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In this in-depth article, you'll discover:
Pearls rank among our most ancient gemstone materials, treasured in jewelry for approximately 6,000 years. Historical records document commercial pearl harvesting dating back at least 2,500 years. The cultivation of "blister pearls" began in China as early as the 13th century CE, demonstrating humanity's long fascination with these organic gems.
While oysters remain the best-known pearl producers, various mollusks including clams, mussels, and abalone can create pearls. Today, truly natural pearls exist as extraordinary rarities. In wild populations, only one in several million mollusks will ever produce a pearl. This extreme scarcity explains why cultured or farm-grown pearls dominate today's market.
A pearl forms when an irritant penetrates deeply enough into a mollusk's shell that the creature cannot expel it. The mollusk's shell-producing system responds by coating the irritant with nacre, the lustrous substance lining most shells. Nacre consists of the mineral aragonite combined with an organic binder called conchiolin. The thin nacre layers create a diffraction grating through which light passes, producing a pearl's distinctive luster.
Natural pearls nearly vanished from the market in the late 1800s due to overharvesting. Even today, they remain extremely rare and command extraordinary prices. As natural sources became depleted, the modern era of cultured pearl production began in Japan around 1910. "Perliculture" or pearl farming enables producers to create pearls in greater quantities and larger sizes than would naturally occur.
Despite the addition of alexandrite to modern lists, pearls remain the gemstone most commonly recognized as the June birthstone. Pearls also maintain a strong connection to weddings and, in particular, brides. This association isn't merely clever modern marketing—pearls have symbolized weddings, fertility, and love for thousands of years across many cultures.
For more information on pearl symbolism, see our article on its legends and lore.
The surface iridescence on orient of pearls results from diffraction at the edges of overlapping aragonite crystal plates. These edges also cause the roughness detected in a "Tooth Test." Every pearl displays both a body color and "overtones" of rainbow hues created by this admired phenomenal effect.
Black pearls derive their dramatic coloration from a layer of dark conchiolin showing through the nacre. Their body colors include true black, gray, bronze, dark blue, blue-green, and green. Some specimens display striking metallic overtones. See our article on Tahitian and other black pearls for additional information.
Colored pearls display a pronounced body color—any hue except black or white. The most common body colors include blue pearl varieties, red, purple, violet, yellowish, and green. Typically, colored pearls feature a blue background color. These diverse colors appear more frequently in freshwater pearls than in saltwater varieties.
Darker pearl colors apparently result from dark conchiolin in the pearl's core showing through the thin layers of aragonite crystals.
The fluorescence of natural pearls ranges from inert to strong light blue, yellowish, greenish, or pinkish in both longwave (LW) and shortwave (SW) ultraviolet (UV) light. Cultured pearls may show no reaction or exhibit the same reaction as natural pearls under LW. Freshwater pearls consistently glow yellowish-white when exposed to X-rays.
Natural black pearls may display weak to moderate red, orangish red, or brownish red fluorescence under LW. Dyed black pearls may show variable reactions under LW but never match the fluorescence patterns of natural black pearls.
La Paz pearls exhibit a distinctive strong red reaction under LW UV light.
Cultured pearls represent the pearl equivalent of synthetic gems. Cultured pearls form under the same conditions as their natural counterparts and share identical chemical and physical properties, with a few revealing differences. Unlike laboratory-created gems, however, cultured pearls grow in both saltwater and freshwater farms.
Akoya pearls represent the most well-known and highly prized type of cultured pearl on today's market.
In underwater pearl farms, cultivators carefully insert pieces of mantle tissue and mother-of-pearl seeds or shell beads into bivalve mollusks such as oysters. The animals secrete nacre to coat these irritants, just as they would naturally respond. The composition and structure of this nacre remains essentially identical to naturally-formed nacre.
After this surgical intervention, the oysters convalesce in a "hospital" environment for four to six weeks. Workers then transfer them to cages positioned seven to ten feet underwater. Here, they continue developing for one to six years. The cultivation period varies depending on farm conditions, mollusk species, and the desired pearl characteristics.
In this video, Jake Talve-Goodman of The Concierge Gemologist explains the differences between saltwater and freshwater pearl cultivation techniques. These pearls also typically find different uses in jewelry. Please note: marine mollusks can produce multiple cultured pearls at a time, but these are smaller than single-yield pearls.
Some cultured pearls can be distinguished from natural pearls through X-ray examination at a gemological laboratory. This technique can reveal the seed used to initiate nacre layer formation. You might also spot the seed if a pearl has a drill hole, so use judgment before requesting X-ray testing. Identifying certain cultured pearl types requires more advanced gemological testing methods.
Faux or fake pearls are pearl simulants. While cultured pearls constitute real pearls, simulants aren't pearls at all. Various materials including glass, shell, and plastic can mimic a pearl's luster through surface treatments. Faux pearls have existed for centuries, but with cultured pearl prices at historic lows, there's little incentive to purchase or wear imitations.
To determine whether a pearl is genuine or fake, try the simple "Tooth Test." Gently rub the pearl across your teeth's surface. Genuine pearls will feel slightly gritty or rough, while most imitations feel completely smooth.
Various treatments can change the color of pearls.
The most crucial factor when evaluating a pearl's value is determining whether it's natural or cultured. Contrary to popular belief, whether it's a saltwater or freshwater pearl doesn't affect its value. Natural pearls command significantly higher prices than cultured varieties due to their extreme rarity.
Experts grade all pearls—whether natural or cultured—based on several key factors: luster, nacre thickness, shape, surface quality, color, and size. These properties determine a pearl's overall quality and value. For more detailed guidance on how to assess pearl value, consult our pearl buying guide and cultured pearl appraisal guide.
The more light a pearl's surface reflects and the sharper those reflections appear, the higher its luster. Very high or high luster indicates bright, sharp reflections. Soft or dull luster means the reflections appear weak, fuzzy, and diffused.
The thickness of a pearl's nacre layers affects its durability and directly relates to its orient and luster. Professional gemologists consider 0.25 to 0.35 mm good commercial grade, while 0.35 to 0.5 mm represents gem grade. Unfortunately, cultivation challenges often lead to faster harvests, affecting nacre thickness. Consequently, the highest grades now typically max out around 0.4 mm.
While measuring nacre isn't always feasible, you can gauge its thickness by assessing a pearl's luster and orient quality.
The closer a pearl approaches perfect roundness, the higher its value. Symmetry represents a secondary value factor. Typically, an oval pearl commands more value than a baroque shape.
Round pearls form almost perfect spheres with less than 2% variation in diameter. To determine whether a pearl is truly round, professional testers roll it across a table. If it rolls straight, it's classified as round. If the pearl veers off more than slightly, experts consider it semi-round. Semi-round pearls (also called off-round or near-round) represent slightly imperfect spheres. Their diameter variation falls between 2% and 5%.
Ringed or circled pearls display regular streaks, rings, or grooves. These markings must appear perpendicular to the rotation axis and cover more than one-third of the surface area.
Baroque pearls exhibit irregularity in every direction without any rotation axis. Semi-baroque pearls, however, display at least one rotation axis, allowing them to spin on one end like a top. Baroque subdivisions include drop, button, pear, and oval shapes.
Surface grading is done with the naked eye rather than a loupe. Two principal factors influence the surface grade: the size or texture of the surface irregularities and how much surface area they cover.
The Tahitian pearl grading system uses the following grades. However, the principles apply to all pearls.
When grading pearl colors, experts must consider body color and overtone simultaneously. Not all pearls display overtones, and those that do show tremendous variation.
For light pearls, body color values progress from white to silver, then cream, and finally into increasingly yellow shades. With orient present, top values belong to light rose pearls (white body color with pink overtones). Next come cream rose pearls, featuring cream body color with deep rose overtone.
The most valuable fancy pearls display cream body colors with rose overtone plus green or blue secondary overtones.
For black pearls, darker colors closer to true black command higher values. Top-grade black pearls feature a green overtone called "peacock green." Multiple overtone colors rank next in value.
See our specialized guides to freshwater pearls and saltwater pearls for comprehensive information on pearl-producing mollusk species plus natural and cultivation sources worldwide.
Gemologists measure pearls in millimeters, grains, and mommes. One jeweler's grain equals 0.25 carats. A momme represents a quantity measurement for pearls, with one momme equaling 75 jeweler's grains or 18.75 carats. (Note that "grain" carries different values in other measurement systems).
Experts measure round and off-round pearls by their shortest diameter. Pearls in other shapes require measurement along their longest and second-longest dimensions.
As with any gemstone, larger specimens occur less frequently, commanding higher prices per weight unit. Round pearls typically range from 2 to 9 mm in diameter. Baroque pearls can reach impressive sizes up to 50 mm.
For information about large and famous named pearls, see our listings for freshwater and saltwater pearls as well as our article on seven famous pearls.
Pearls develop in symmetrical round and pear shapes. Jewelers refer to squat pear shapes as egg shapes, while elongated pear shapes become drop shapes.
The industry generally names pearls after their distinctive shapes. Beyond rounds and drops, you might encounter stick pearls, button pearls, seed or rice pearls, and many other shape-based classifications.
Baroque refers to any irregularly shaped pearl. These unique pearls carry many different trade names. Although symmetrical spheres remain the most popular and traditional pearl shape, the unusual forms baroques can assume often inspire truly unique jewelry designs.
Note how the baroque pearl's irregular shape captures the form of a torso from both front and back. Pendant in the form of a siren, baroque pearl with enameled gold mounts set with rubies. Probably ca. 1860, European, height 10.6 cm. The Jack and Belle Linsky Collection, 1982. Metropolitan Museum of Art, New York. Public Domain. (Cropped to show detail).
The trade classifies baroque pearls with poor luster as "slugs."
Sometimes jewelers use the term "keshi" to describe almost any baroque pearl. However, strictly speaking, this term refers to all-nacre, non-nucleated pearls that form spontaneously during South Sea pearls cultivation, as well as pearls intentionally nucleated with mantle pieces. See our article on keshi pearls for more information.
"Bombay" describes pearls with cream body color featuring rose overtone.
"Ceylon" or "Madras" refers to white or cream pearls displaying fancy overtones of green, blue, or purple.
La Paz pearls originate from coastal waters off Baja California, Mexico.
Today, the term "Oriental" applies exclusively to natural pearls from the Persian Gulf. Historically, this term referenced any pearls of saltwater origin.
Many gem materials have been called pearls due to their appearance and watery origins. Some of these materials are now referred to as calcareous concretions or non-nacreous pearls. They aren't true pearls, despite their names. Some well-known examples of calcareous concretions include conch pearls and tridacna pearls.
So-called blister pearls develop attached to the inside of a mollusk's shell. These dome-shaped, hollow pieces aren't true pearls.
Some artisans create mabe pearls by filling blister pearls and gluing them to a shell backing.
Other "pearls" in name only include the following:
Mother of pearl consists of the iridescent inner nacre layer found in most seashells—it isn't a pearl type. Skilled artisans can transform mother of pearl into beautiful jewelry and decorative objects.
Jake Talve-Goodman of The Concierge Gemologist introduces viewers to the fascinating world of mother of pearl and discusses its formation, sourcing, valuation, symbolism, and jewelry and decorative use.
Although pearls are delicate, jewelry makers have successfully made wonderful pieces from them for thousands of years. Nevertheless, if you want to enjoy your pearl jewelry for even a fraction of that time, you should exercise some caution. Along with opals, pearls merit their own detailed care guide.
Here are some basic guidelines:
If you’re fascinated by pearls and their timeless elegance, this comprehensive guide will help you understand everything you need to know about these unique organic gems. Natural pearls are increasingly rare treasures as most pearls on the market today are cultivated, since they now occur extremely rarely in nature. While they require special care, pearls have an enduring appeal for jewelry, particularly as the traditional June birthstone.
