Research News

Freshwater Pearls vs. Saltwater Pearls: Understanding the Difference

Phoebe Shang

Pinctada maxima shells
This colorful strand contains all four major cultured pearl types. Seen here are pink freshwater, white akoya, gray Tahitian and golden South Sea pearls that range from 9.5 – 12 mm. Courtesy: Yoko London @yokolondonpearls

Different types of pearls vary in size, color, luster and value because they are formed by different mollusks in freshwater and saltwater environments around the world. From colorful freshwater pearls to the classic white glow of Akoya pearls, each type offers its own unique appeal.

Understanding these differences will help you speak more confidently with your customers and guide them towards the pearls that fit their style and budget. Below, we take a closer look at what sets each type apart.

In this article, we’ll cover:

  • Freshwater Pearls
  • Saltwater Pearls
    • Akoya
    • Tahitian
    • South Sea
  • Cultured vs. Natural pearls
  • How to choose quality pearls 
    • The GIA 7 Pearl Value Factors
    • GIA Pearl Reports

 

Cultured freshwater baroque pearls in pink, peach, blue, white
This strand features multi-color cultured freshwater baroque pearls in a palette of pastel hues. The varied colors—from delicate pinks and peaches to cool silvers, lavenders and creamy whites—highlight the diversity and versatility of freshwater pearls. Courtesy of Yoko London @yokolondonpearls

FRESHWATER PEARLS 

Freshwater pearls are known for their versatility, wide color range and friendly price point. Cultured primarily in lakes and ponds, they have evolved dramatically over the past two decades. Advances in farming techniques have resulted in pearls that are larger, rounder and more lustrous than earlier generations—making today’s freshwater pearls more refined than ever before. 

Color, Luster & Orient

In addition to classic white, they commonly appear in soft pastel shades such as purple, pink, peach, yellow, and lavender. Their luster can range from soft and satiny to bright and reflective. High-quality freshwater pearls may also show overtones, subtle secondary hues that sit over the main bodycolor, and occasionally orient, a delicate, rainbow-like iridescence that appears to shimmer across the surface. These optical effects are created as layers of nacre interact with light, giving the pearl depth and dimension. 

Baroque cultured freshwater soufflé pearls from China
These large, cultured freshwater “Soufflé” pearls from China range from 16–23 mm and are known for their soft luster and baroque shapes. Formed using a mud-like nucleus that can create internal voids, they are typically lightweight. Courtesy of Jack Lynch at Sea Hunt Pearls, San Francisco, CA.

Culturing Methods

Freshwater pearls are cultured in freshwater Hyriopsis mussels in rivers, lakes and ponds. While many freshwater pearls have traditionally been tissue-nucleated rather than bead-nucleated, bead-cultured freshwater pearls have become increasingly common in today’s market.

Tissue-Nucleated Pearls

In tissue nucleation, a pearl farmer places a small piece of mantle tissue into a mollusk to initiate pearl growth. The mollusk then secretes layers of nacre through the same natural biological process that forms natural pearls. Tissue-nucleated freshwater pearls are often composed almost entirely of nacre, rather than containing a shell bead.

This “solid nacre” structure contributes to:

  • Durability
  • Resistance to chipping
  • A soft, layered glow

Bead-Nucleated Pearls

Some freshwater pearls are bead-nucleated, meaning a shell bead and mantle tissue are inserted to initiate growth. Increasingly common in today’s market, this method can result in larger pearl sizes and rounder, more symmetrical shapes.

Size

Freshwater pearls typically range from 6 to 12 millimeters, though sizes can vary widely depending on cultivation time and technique. Smaller pearls are common in classic strands and fashion jewelry, while larger freshwater pearls have become increasingly available thanks to modern culturing advancements.

In recent years, improved methods have allowed freshwater pearls to grow rounder and larger than in the past. Edison pearls, in particular, can range from 11 to 16 millimeters or more, rivaling the size of Tahitian and even South Sea pearls.

Because freshwater mussels can produce multiple pearls at once and are cultivated in large numbers, freshwater pearls offer the broadest range of colors and sizes at accessible price points. 

Bead-nucleated pink to purple freshwater cultured pearls
This necklace of 11–15 mm natural-color cultured freshwater pearls displays pinkish lavender to mauve hues. Their size and shape are consistent with bead-nucleated freshwater pearls, highlighting how freshwater cultivation can produce larger, more uniform pearls comparable in appearance to some saltwater pearls. Courtesy of Yoko London @yokolondonpearls

Edison Pearls: A Modern Innovation

In recent years, a newer category known as Edison pearls has redefined what freshwater pearls can be. Unlike traditional freshwater pearls, Edison pearls are bead-nucleated, meaning a round bead is inserted into the mussel along with mantle tissue. This allows them to grow larger and more consistently round.

Edison pearls often range from 11 to 16 millimeters or more, rivaling the size of South Sea and Tahitian pearls. They are known for strong luster and vibrant colors, including white, metallic pink, peach and purple.

By combining modern culturing techniques with freshwater farming, Edison pearls bridge the gap between traditional freshwater pearls and larger saltwater varieties — often at a more accessible price point.

Where They’re Grown

Freshwater pearls are cultivated primarily in China, which leads global production. Because these mussels can produce multiple pearls per cycle and do not require a bead nucleus in most cases, freshwater pearls remain one of the most widely available, affordable and versatile pearl types in the market. 

This strand of white akoya pearls has been designated hanadama by the GIA laboratory in Japan, a distinction reserved for pearls with exceptional luster, surface, nacre and matching quality.
This strand of white akoya pearls has been designated hanadama by the GIA laboratory in Japan, a distinction reserved for pearls with exceptional luster, surface, nacre and matching quality.

SALTWATER PEARLS

Saltwater cultured pearls include well-known types such as akoya, South Sea and Tahitian pearls. They are cultivated in marine environments in regions including Japan, China and Vietnam (akoya), Australia and Southeast Asia (South Sea), and French Polynesia (Tahitian). Each has distinct characteristics shaped by its host mollusk and environment.

AKOYA PEARLS

Akoya pearls are the classic white pearls most people envision when they think of a traditional strand. While smaller than other pearl types, they are celebrated for their round shape and crisp, mirror-like luster and have long been associated with timeless elegance.

Color, Luster & Overtones

Akoya pearls are best known for their white bodycolor and sharp, mirror-like luster. Light reflects sharply off the surface, creating a bright, almost reflective sheen — one of the hallmarks of high-quality Akoya pearls.

Overtones — subtle secondary hues that float over the surface — add another dimension to their ethereal beauty.  

Common Akoya overtones include:

  • Rose (or Rosé) – a soft pinkish glow that enhances warmth
  • In addition to classic white, some Akoya pearls naturally display a rare blue bodycolor. Blue Akoya pearls often feature silvery-gray tones with cool overtones, offering a distinctive and contemporary alternative to traditional white strands. 
Bicolor tourmaline ring with a halo of blue akoya pearls
This design pairs a bicolor tourmaline with a halo of blue Akoya pearls, whose pink and green overtones enhance the gemstone’s shifting hues and add depth to the composition. Once overlooked, rare blue Akoya pearls are now emerging as a sought-after trend. Courtesy of Assael Pearls

Culturing & Nacre 

Akoya pearls are produced by the saltwater oyster Pinctada fucata. They are bead-nucleated. This means a pearl farmer places a round shell bead and a piece of mantle tissue into a mollusk to initiate pearl growth. The mollusk then coats the nucleus with layers of nacre through the same natural biological process that forms natural pearls. 


During cultivation:
•    Each oyster typically produces one pearl at a time
•    Culturing generally takes 10 to 24 months
•    The pearls develop tight, even nacre layers that contribute to their sharp luster
Cultivated in cooler waters, Akoya pearls form nacre more slowly, resulting in a finer structure that gives them their signature bright, mirror-like luster.

Size

Akoya pearls are typically smaller than Tahitian or South Sea pearls, most commonly ranging from 6 to 9 millimeters. Pearls over 9 millimeters are considered larger and become increasingly rare — and more valuable.

Their more modest size contributes to their refined, classic look. Akoya pearls are especially popular in traditional strands where uniformity and roundness are emphasized.

Because each oyster typically produces only one pearl at a time and Akoya pearls are often harvested after a relatively short growth period, they generally do not reach the larger sizes seen in other pearl types.

Hanadama: Akoya Pearls with Exceptional Quality

Now Recognized on GIA Reports

Hanadama (meaning “flower pearl”) is a historical Japanese trade term used to describe akoya cultured pearls with Excellent luster, Excellent to Very Good nacre and matching (for pairs and strands) and clean to slightly spotted surfaces. 
On qualifying GIA Pearl Classification Reports, a hanadama comment may be included for akoya cultured pearls that meet strict grading criteria. To receive this designation, pearls must display:
•    Round to near-round shapes 
•    White body color (with or without overtones) 
•    Excellent luster, nacre quality and matching 
•    Clean to slightly spotted surfaces 
Hanadama quality pearls are among the most prized treasures in the world of akoya cultured pearls.

Where They’re Grown

Akoya pearls are cultivated primarily in Japan, Vietnam and China, with Japan historically recognized as the birthplace of modern pearl culturing.

Their saltwater environment, combined with careful farming practices, helps produce their signature round shape and brilliant shine.

In recent years, certain freshwater pearls have been marketed as “Freshwater Akoyas” even though they are not akoya pearls. This terminology is misleading to consumers.

Multicolored Tahitian pearl necklace strand.
This 18-inch necklace features lustrous cultured Tahitian pearls displaying a wide range of bodycolors, enhanced by colorful overtones and subtle orient.

TAHITIAN PEARLS

Tahitian pearls are known for their dark bodycolors and colorful overtones. Often referred to as “black pearls,” they are not truly black — but instead display a wide range of dark, naturally occurring bodycolors from gray to silver to brown.

With their larger average size (8 – 14 mm) and rich tones, Tahitian pearls offer a modern, statement-making alternative to classic white strands.

Color, Luster & Overtones

Tahitian pearls commonly appear in shades of:
•    Charcoal gray
•    Silver
•    Green
•    Brown
High-quality Tahitian pearls often display strong overtones — flashes of green, blue, purple, pink or bronze that shimmer across the surface. This can give them a metallic-looking sheen.

Overtones/ Orient
•    Cherry (pink to magenta overtone) 
•    Peacock (green with hints of rose or purple). The most valuable.
•    Aubergine (deep purple overtone)

Their luster ranges from bright to satiny, with high-quality pearls exhibiting a deep, reflective glow that enhances their rich color.

Earrings set with peacock Tahitian pearls and emerald cut pink tourmalines
These earrings feature 12.5 mm “peacock” Tahitian pearls paired with emerald-cut pink tourmaline. The pearls’ shifting pinkish-purple orient is beautifully enhanced by the tourmaline’s vivid pink hue. Courtesy of Assael Pearls

Culturing & Growth

Tahitian pearls are bead-nucleated and grown in the saltwater oyster Pinctada margaritifera, commonly known as the black-lipped oyster.

Typically:
•    One pearl is produced per oyster at a time
•    Culturing takes about 18 to 24 months
The dark inner shell of the oyster contributes to the pearl’s natural bodycolor.

Size

Tahitian pearls range from 8 to 14 millimeters. Sizes above 14 millimeters are less common and can command higher prices.

Size is influenced by both growth time and environmental conditions. Larger Tahitian pearls take longer to grow and are more limited in supply. As a pearl grows over time, it becomes more likely to develop slight irregularities in shape or surface. Large pearls with round, smooth surfaces are especially rare and valuable.

Where They’re Grown

Tahitian pearls are cultivated primarily in French Polynesia, particularly around Tahiti and its surrounding islands. Warm lagoon waters and careful farming practices help produce their distinctive tones and surface quality.

Because production is limited to specific regions and yields are lower than freshwater pearls, Tahitian pearls tend to command higher prices.

Phoebe Shang, a senior writer at GIA, is a Graduate Gemologist.

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