Please ensure Javascript is enabled for purposes of website accessibility.
Search
Search
Search

GIA 4Cs Diamond Blog

GIA 4Cs Diamond Blog

September Birthstone: What You Need to Know About Sapphire

The September birthstone is sapphire – a gem that’s been cherished for thousands of years. Sapphire is one of the most popular colored stones because of its beautiful blues. It also comes in a rainbow of other colors. Here’s how to pick a stunning one.

In this post, we cover:

Gemological Properties of Sapphire
Sapphire History & Lore
Where Sapphire Comes From
Qualities to Look for in Sapphire
Sapphire Care & Cleaning

Gemological Properties of Sapphire

The colors of sapphire enchant.

The colors of sapphire enchant. Faceted stones (from left to right): 6.36 carat (ct) pinkish orange “padparadscha,” 1.63 ct pink, 4.76 ct violet, 5.43 ct violet-purple, 3.03 ct blue, 2.12 ct blue, 8.06 ct yellow, 3.46 ct yellow, 2.00 ct orange and 1.01 ct deep orange. Photo: Robert Weldon/GIA. Courtesy: Dr. Edward J. Gübelin Collection and Bill Larson, Pala International

The September birthstone, sapphire, comes in a range of colors in addition to the familiar blue. Called “fancy sapphires,” these are violet, green, yellow, orange, pink, purple, black, brown and intermediate hues. Sapphire can be colorless, too. That’s because the gem belongs to the mineral species corundum, which is composed of aluminum and oxygen. In its purest state, corundum is colorless. However, colorless corundum is rare. Most corundum contains trace amounts of additional elements including iron, titanium, magnesium, vanadium, and chromium that replace aluminum in the corundum structure. The coloration of blue and fancy sapphires involves interactions between these impurity elements—sometimes in combination with imperfections in the gem’s crystal structure—that absorb light and impart color into this otherwise colorless mineral.

Blue in sapphire requires interaction between impurities of iron and titanium, whereas chromium is key to the pink in pink sapphires and the red color of ruby, which also belongs to the corundum mineral species. (Red corundum is the only color not called sapphire – it is called ruby.)

Any color of corundum can show a phenomenon called asterism, or the star effect. This phenomenon usually appears as a six-ray star pattern across a cabochon-cut stone’s curved surface when the gem is examined in direct sunlight or with a single intense light. Asterism is caused by the presence of numerous tiny, needle-like inclusions of rutile or hematite oriented in specific directions.

The star, or asterism, in this 5.43 ct blue sapphire is heavenly.

The star, or asterism, in this 5.43 ct blue sapphire is heavenly. Photo: Robert Weldon/GIA. Courtesy: Fu Gemstone Import, Seattle, WA.

Another interesting variety is color-change sapphire. These fascinating stones appear to be a different color under different lighting conditions, most often going from violetish blue in daylight or fluorescent lighting to deep reddish purple in incandescent light. Their presence adds a special dimension to the options available for the amazing September birthstone.

A cluster of sapphire crystals from Myanmar, a faceted blue-green sapphire from Kenya and a faceted blue sapphire from Montana.

Pictured here are a cluster of sapphire crystals from Myanmar, a faceted blue-green sapphire from Kenya and a faceted blue sapphire from Montana. Photo: Robert Weldon/GIA. Courtesy: (Rough) Bill Larson, Pala International; (Left) Columbia Gem House; (Bottom) Dr. Edward J. Gübelin collection.

Some of the many colors of sapphire are on display in “Dawn” – a one-of-a-kind necklace that features 450 carats of sapphire beads.

Some of the many colors of sapphire are on display in “Dawn” – a one-of-a-kind necklace that features 450 carats of sapphire beads. Courtesy: Denise James

Sapphire History & Lore

The September birthstone has traditionally symbolized sincerity, truth, faithfulness and nobility. For countless centuries, sapphire has adorned royalty and the robes of the clergy. The elite of ancient Greece and Rome believed that blue sapphires protected their owners from harm and envy. The clergy of the Middle Ages wore sapphires because they symbolized Heaven.

The September birthstone was also reputed to have healing powers. Medieval Europeans believed that sapphire cured plague boils and diseases of the eye. It also was thought to be an antidote to poison.

A dragonfly brooch studded with a 38.82 carats of pink, green, blue and yellow fancy sapphires and 5.74 carats total weight of diamonds.

A dragonfly brooch studded with a 38.82 carats of pink, green, blue and yellow fancy sapphires and 5.74 carats total weight of diamonds might make you believe in the magical powers of the gem. Photo: Robert Weldon/GIA. Courtesy: Pioneer Gems

Famous sapphires include the Rockefeller Sapphire, a 62.02 ct rectangular step cut stone that was unearthed in Myanmar (Burma). Acquired in 1934 by financier and philanthropist John D. Rockefeller, Jr. (1874–1960) from an Indian maharaja, the gem was recut and remounted over the years. The sapphire was first set as a brooch and later as a ring featuring two triangular brilliant cut diamond side stones.

The Rockefeller Sapphire is a 62.02 ct rectangular step-cut sapphire weighing 62.02 ct.

The Rockefeller Sapphire is a 62.02 ct rectangular step-cut sapphire weighing 62.02 ct. Here it is flanked by cut-cornered triangular cut diamonds, mounted in a platinum ring signed Tiffany & Co. Courtesy: Christie’s Images Ltd., 2015

The Starry Night Sapphire is another famous gem. Also originating from Myanmar, the Starry Night Sapphire is a 111.96 ct cabochon-cut gem whose magnificent six-rayed star is a fine example of asterism.

The Starry Night Sapphire comes from Myanmar, one of the most important sources of the gem.

The Starry Night Sapphire comes from Myanmar, one of the most important sources of the gem. The gemological phenomenon asterism is responsible for creating the six-rayed star. Photo: Robert Weldon/GIA. Courtesy: Benjamin Zucker

In addition to being the September birthstone, sapphire is also the gem commemorating the 5th and 45th wedding anniversaries.

Where Sapphire Comes From

Kashmir, Myanmar and Sri Lanka are three historically important sources for sapphire. Significant quantities of the September birthstone have also been found in Australia, Thailand, Cambodia, Madagascar and the United States (Montana), among other countries in Asia and Africa.
Sapphires were discovered in Kashmir around 1881, when a landslide high in the Himalayas exposed a large pocket of velvety “cornflower” blue crystals. As the spectacular sapphires began to appear farther south, the Maharaja of Kashmir—and his army—took control of the new locality. From 1882 to 1887, thousands of large, beautiful crystals were recovered. In this short season of six years rests Kashmir sapphire’s reputation as one of the world’s most coveted gems. Production has been sporadic since then, but auction houses occasionally sell fine pieces of Kashmir sapphire.

A magical pool … a drop of the sky … a slice of eternity. This 3.08 ct cushion cut Kashmir sapphire conjures such visions.

A magical pool … a drop of the sky … a slice of eternity. This 3.08 ct cushion cut Kashmir sapphire conjures such visions. Photo: Robert Weldon/GIA. Courtesy: Edward Boehm, RareSource

The Himalaya Mountains are the source of Kashmir’s beautiful blue sapphires.

The Himalaya Mountains are the source of Kashmir’s beautiful blue sapphires. Photo: Robert C. Kammerling/GIA

The Mogok area of Myanmar is another locale famed for producing the September birthstone. Jungle-clad hills hemmed by mountains make a dramatic landscape. Sapphire typically occurs alongside ruby deposits, but in much lower quantities than its red counterpart. ”Burmese” sapphire, as it is still called by many, can possess a rich, intense blue hue, which has made it particularly prized.  Myanmar is also a noted source of jadeite jade, spinel, zircon, amethyst, peridot and other fine gem materials.

A scenic view near Mogok rivals the beauty of the sapphires hidden underground.

A scenic view near Mogok rivals the beauty of the sapphires hidden underground. Photo: James E. Shigley/GIA

For more than 2,000 years, Sri Lanka has been a source of fine sapphire. The blue stones mined from the alluvial gravels of this “jewel box of the Indian Ocean” can display remarkable brilliance and saturation. In addition, the island’s milky white “geuda” sapphires can be heat treated to a rich blue color.

Sri Lanka is one of the few sources for padparadscha (from the words for “lotus color” in Sinhalese) sapphires. Poetic descriptions for this light to medium pinkish orange to orange-pink sapphire include “salmon,” “sunset” and ”ripe guava.” Padparadschas are quite coveted and have a very high per-carat value.

This gem-rich island is also home to ruby, spinel, garnet, tourmaline, topaz and many more gems.

Using the same rudimentary washing techniques as generations before them in Sri Lanka, miners search for sapphire among the gravels in a local stream.

Using the same rudimentary washing techniques as generations before them in Sri Lanka, miners search for sapphire among the gravels in a local stream. Courtesy: Afsaneh Tazari

The spellbinding beauty of this 6.66 ct gem from Sri Lanka shows why padparadscha sapphires are so prized.

The spellbinding beauty of this 6.66 ct gem from Sri Lanka shows why padparadscha sapphires are so prized. Photo: Robert Weldon/GIA, Dr. Edward J. Gübelin Collection

Thailand is a source of sapphire and a major cutting and treatment center. In dense jungle crossed by dirt roads, miners dig for sapphire in Chanthaburi Province. Sapphires from Myanmar and Cambodia often end up in Chanthaburi for cutting and treatment, and are also sent to Bangkok, an important gem hub.

In the distance, a mining pit dots the tropical terrain of Chanthaburi, Thailand.

In the distance, a mining pit dots the tropical terrain of Chanthaburi, Thailand. Photo: Vincent Pardieu/GIA

Sapphire Qualities to Look For

Here are some tips for picking a stunning sapphire.

  • Color: The value of most sapphires—both blue and fancy color is based on a combination of hue, tone and saturation. Hue is your first impression of a gem’s basic color. Tone is the darkness or lightness of a color. Saturation is a color’s strength or intensity.
Each sapphire color has its own quality variations. In general, though, the more intense the color and the fewer zones of unattractive color, the more valuable the stone. The most highly valued blue sapphires are velvety blue to violetish blue, in medium to medium-dark tones. The saturation should be as strong as possible without darkening the tone and compromising brilliance. Blue sapphires with these qualities command the highest price per carat.
Zoning in sapphires of all colors is common and, especially when apparent in the stone viewed face up, reduces the value of the sapphire. It is important to examine a stone from all angles to determine the presence or degree of zoning before making a purchasing decision.
Other factors that help determine the value of a sapphire are clarity, cut, proportions, rarity and market demand.
These fancy sapphires range from yellow to highly saturated reddish orange.

For those who prefer warm-colored gems, the September birthstone does not disappoint. These fancy sapphires range from yellow to highly saturated reddish orange. Photo: GIA & Tino Hammid. Courtesy: Varujan Arslanyan

  • Cut: Fashioned sapphires appear most commonly in cushion and oval shapes with brilliant-cut crowns and step-cut pavilions. Blue sapphire cut into trilliant (triangular), emerald, pear and marquise shapes are also available.
The cushion cut is particularly popular for sapphires, like this 4.47 ct blue stone.

The cushion cut is particularly popular for sapphires, like this 4.47 ct blue stone. Photo: Robert Weldon/GIA. Courtesy: Bear Essentials

Asterism in a sapphire will only be revealed if the stone is cut as a cabochon. A finished stone’s attractiveness depends on the star’s orientation and the cabochon’s symmetry, proportions and finish.

Look for a cabochon with a symmetrical outline and a star that’s centered when the gem rests on its base. The dome of the cabochon should be fairly high—about two-thirds of the stone’s width—to focus the star sharply. If it’s too high, the phenomenon loses its graceful motion when the stone is tilted. Excessive height also makes the stone difficult to mount.

  • Clarity: Sapphires typically have some inclusions. As a general rule, inclusions make a stone less valuable, and the price can drop significantly if they threaten the stone’s durability. Sapphires with extremely high clarity are rare and very valuable.
  • Carat Weight: Sapphires can range in size from a few points to hundreds of carats. Large blue sapphires are more readily available than large rubies. However, most commercial-quality blue sapphire weighs less than 5 carats. Large padparadscha or color-change sapphires are exceedingly rare.
Sapphires are the stars in these earrings. They were especially popular during the Art Deco era of the 1920s and ‘30s, a look that you can get in an engagement ring.

Sapphires are the stars in these earrings. They were especially popular during the Art Deco era of the 1920s and ‘30s, a look that you can get in an engagement ring. Courtesy: Genevive

  • Treatments: As you shop, be aware that sapphires are often treated in some way to improve their color and other aspects of their appearance. Heating is one common treatment, particularly for blue sapphires. The results are stable and durable, and heat-treated blue sapphires typically retain their enhanced effects permanently. Because of this, the practice is commonly accepted in the colored stone market.
Lattice diffusion is another common treatment that can improve color. This involves packing a sapphire into a crucible with coloring agents such as titanium or beryllium, and then heating them almost to a melting point. This allows the elements to enter the stone and alter its color. For example, pink sapphires may turn orange or pinkish orange (padparadscha) with beryllium diffusion. While this treatment is also considered permanent, in some cases (such as titanium-diffused blue sapphire) the added color is so shallow it could be removed if the stone was chipped or had to be recut.
A less stable, and relatively less common, treatment is the filling of surface-reaching fractures with oil, epoxy, resin or a high-lead-content glass. In some cases, a colored filler is used.
Sapphires treated with a filler require special care. The filler can be damaged through contact with a variety of chemicals or high heat. Even relatively mild substances like lemon juice can cause alteration of high-lead-content glass.
Be sure to ask if your sapphire has been treated before you buy. A GIA Colored Stone Identification Report  will tell you if a stone is natural or synthetic and whether it has been treated in any fashion.

Sapphire Care & Cleaning

The September birthstone is relatively hard, ranking 9 on the Mohs scale. It has excellent toughness and no cleavage, which is a tendency to break when struck. This makes it a great choice for rings and other mountings subject to daily wear.

Corundum is stable under normal wearing conditions, which means it’s resistant to the effects of heat, light and common chemicals. Boric acid powder will etch the surface of even untreated stones. Fracture-filled, cavity-filled and dyed stones can be damaged by even mild acids like lemon juice.

Warm, soapy water is always a safe choice for cleaning the September birthstone. Ultrasonic and steam cleaners are usually safe for untreated, heat-treated and lattice-diffusion-treated stones. Fracture-filled, cavity-filled or dyed material should only be cleaned with a damp cloth.

Now that you know all about sapphire, you’re probably in the mood to buy a beautiful one. Our Sapphire Buying Guide can help you make a great choice.

July Birthstone: What You Need to Know About Rubies

Ruby is the July birthstone – and it’s one of the most coveted of gems. Called the “king of gems” in ancient India, today it can command the highest per-carat price of any colored stone. Here’s what you need to know about this beautiful gem.

In this post, we cover:
Gemological Properties of Ruby
Ruby History & Lore
Where Ruby Comes From
Qualities to Look for in Rubies
Ruby Treatments, Care & Cleaning

 

July Birthstone: Gemological Properties of Ruby

Ruby, the July birthstone, is a variety of the mineral corundum that contains trace amounts of the element chromium, which causes its color. The more chromium present, the stronger the color red. Chromium can also cause red fluorescence, which adds to the intensity of the color. Fluorescence is visible light temporarily emitted by some gem materials when they are exposed to high-energy sources such as ultraviolet light (as in sunlight), X-rays or lasers.

Some rubies form in marble, when heat and pressure act on minerals in limestone. These rubies tend to be highly prized, as they have a higher concentration of chromium and little iron, which is an ideal recipe for a bright red color. They also tend to be highly fluorescent.

Other rubies are found in basalt, which forms when molten lava cools and solidifies. Basalt-hosted rubies typically have significantly more iron than marble-hosted rubies and thus are darker. A higher iron content can also mask the fluorescence, eliminating that extra glow of red color.
Still other rubies form in an amphibole-bearing gneiss (a coarse-grained metamorphic rock). These rubies tend to have good color, though they have more iron than the marble-hosted stones and less than those from basalt.

Gemologists love the July birthstone because synthetic ruby was used to create the first laser in 1960. They also consider chromium to be the “rock star” of trace elements.
Consumers love ruby for its intense red color and because it’s a 9 on the Mohs scale of hardness, just below diamond. As such, it is a very durable stone that holds up well to daily wear in rings and other jewelry.

A look at these earrings featuring 8.16 carats of ruby, 1.78 carats of marquise diamonds, and 1.69 carats of round diamonds shows why we are enchanted by the gem. Courtesy: Omi Privé

 

July Birthstone: Ruby History & Lore

A prized gem like ruby naturally comes with many attributes. Because it resembles the color of blood, ancients believed it could stop hemorrhaging. The July birthstone was also thought to cure inflammatory diseases and soothe anger. Burmese warriors believed it made them invincible in battle. Medieval Europeans maintained that rubies bestowed health, wisdom, wealth and success in love.

In addition to being the July birthstone, ruby is traditionally given for the 15th and 40th wedding anniversaries.

The Harry Winston Ruby Slippers are a famous example of the July birthstone in a spectacular setting. To commemorate the 50th anniversary of the movie “The Wizard of Oz,” the House of Harry Winston fashioned a pair of red slippers featuring 4,600 rubies weighing an estimated 1,350 carats. When they were created in 1989, they were valued at $3 million.

4,600 rubies weighing an estimated 1,350 carats glitter in the slippers; another 50 carats of diamonds accent the unique creation.

Harry Winston’s famed ruby slippers were exhibited at GIA in December 1997. Some 4,600 rubies weighing an estimated 1,350 carats glitter in the slippers; another 50 carats of diamonds accent the unique creation. Courtesy: Harry Winston

 

July Birthstone: Where Ruby Comes From

Our search for the July birthstone starts in Myanmar (formerly known as Burma). For more than five centuries, the Mogok area in Myanmar has produced some of the finest rubies – vibrant red beauties softened by light-scattering inclusions and a glowing red fluorescence. The region is a place of weathered marble and ancient Buddhist temples.

Golden spires of a monastery near Mogok are flashes of color along the mountainside.

Golden spires of a monastery near Mogok are flashes of color along the mountainside. Photo: Robert C. Kammerling/GIA

Ruby crystals intertwined with their matrix rival the beauty of finished gems from Mogok.

These ruby crystals intertwined with their matrix rival the beauty of finished gems from Mogok. Photo: Robert Weldon/GIA. Courtesy: Bill and Jeanne Larson

Vietnam is another important source for marble-hosted rubies. The Luc Yen region, where rainforest-clad mountains rise over broad paddy fields, produces rubies of red to purplish red color. Today, artisanal miners work the soil in hopes of finding a gem that will change their fortunes.

Small village sits at the base of the mountains in the ruby-bearing Luc Yen region.

A small village sits at the base of the mountains in the ruby-bearing Luc Yen region. Photo: Vincent Pardieu/GIA

Rubies from Luc Yen and other locales in Vietnam star in these four rings and necklace.

Rubies from Luc Yen and other locales in Vietnam star in these four rings and necklace. Photo: Shane McClure/GIA

4.04 carat (ct) ruby came from Mozambique, the pre-eminent source of commercial and fine rubies.

This fine 4.04 carat (ct) ruby came from Mozambique, the pre-eminent source of commercial and fine rubies. Photo: Robert Weldon/GIA. Courtesy: Evan Caplan, GemFields

Mozambique is an important new, amphibole-related source for the July birthstone. This African nation is home to the prolific mines at Montepuez. Rubies found there have been compared to the famed gems of Mogok.

For many years in the late 1900s, the basalt-related ruby deposits along the border between Thailand and Cambodia were the major source of rubies in the marketplace. Other important producers include Sri Lanka, Tanzania and Madagascar.

Rubies from Madagascar are a bright, slightly orangy red.

Rubies from Madagascar are a bright, slightly orangy red. Photo: Robert Weldon/GIA. Courtesy: Allerton Cushman & Co., Sun Valley, Idaho

 

July Birthstone: Qualities to Look for in Rubies

  • Color: Color is the most important quality factor for the July birthstone. The finest rubies have a pure, vibrant red to slightly purplish red color. A color that’s too orangy or too purplish is considered less desirable. The highest-quality rubies have vivid color saturation that is not too dark.
  • Clarity: People in the trade expect rubies to have at least some inclusions, because inclusion-free rubies are rare. The impact of inclusions on the value of a stone depends on their visibility. Obvious inclusions or inclusions that reduce transparency or brightness can lower a ruby’s value.
  • Cut: A ruby’s crystal shape dictates its suitability for certain cuts. Ruby crystals often have a flat tabular hexagonal shape, but crystals from some sources may be elongate.
  • Carat weight: Rubies are available in a wide range of sizes, but fine-quality rubies over a carat are rare and, not surprisingly, very expensive.
5.00 ct oval ruby is all the more radiant set in 18K rose gold and encircled by 2.53 carats of round diamonds in the halo and band.

This 5.00 ct oval ruby is all the more radiant set in 18K rose gold and encircled by 2.53 carats of round diamonds in the halo and band. Courtesy: Omi Privé

 

July Birthstone: Ruby Treatments, Care & Cleaning

Using warm soapy water is a safe option to clean ruby, the July birthstone. Ultrasonic and steam cleaners are usually safe for untreated, heat-treated and lattice diffusion–treated stones. Fracture-filled, cavity-filled or dyed stones should only be cleaned with a damp cloth.

Rubies are often heat treated to remove purplish coloration, leaving a purer red. The process can also remove “silk” (minute needle-like inclusions) that can cause a gem to appear lighter in tone and be more opaque. The trade typically accepts heat treatment to enhance color, as the treatment is stable to normal conditions of wear and care.

Lattice diffusion is a technique whereby heat and chemicals are used to diffuse a specific element into a gem to change its color. This treatment, too, is typically stable to normal wear and care.

Fracture filling is when a substance is introduced into surface-reaching fissures to make them less visible and thus improve the gem’s appearance. Common fillers include glass and glass-like substances, polymers and resins, and oils.

A high-lead-content glass is often used to fill fractures in rubies and thus improve their apparent clarity. There are many of these glass-filled rubies in the market, and in some cases the glass literally holds together a highly fractured gem. The glass can be damaged through contact with a variety of chemicals. Even relatively mild substances like concentrated lemon juice can etch the filler.

Dyeing with colored oils and filling small surface fissures with epoxies are other treatments. However, they are not permanent. These treatments need special care.

Always ask if your ruby has been treated before you buy. The Federal Trade Commission requires disclosure of treatments that affect a gemstone’s perceived value. A GIA Identification Report is important in identifying if a stone is natural or synthetic and whether it has been treated in any fashion.

Diamond and ruby bracelet shimmers with 20.56 carats of cabochon-cut rubies from Tanzania.

Reminiscent of the geometric shapes used in Art Deco–era jewelry, this diamond and ruby bracelet shimmers with 20.56 carats of cabochon-cut rubies from Tanzania. Photo: Kevin Schumacher/GIA

Whether or not you have a July birthstone, owning a beautiful ruby is a rare and precious thing. And if you love red gems in general, check out our Red Gemstone Buying Guide – Part 1 and Red Gemstone Buying Guide – Part 2 for some striking alternatives to ruby.

June Birthstone: What You Need to Know About Pearls

Coveted for millennia, the June birthstone still reigns supreme as the queen of modern fashion. Elegant, stylish and organic, pearls come in a rainbow of colors and a range of shapes. Our pearl primer will help you choose beautiful ones.

In this post, we cover:
What Is a Pearl?
Akoya, Tahitian, South Sea and Freshwater Cultured Pearls
Pearl History and Lore
Where Pearls Come From
Pearl Qualities to Look For
Pearl Care and Cleaning

"Black Star" faceted Tahitian pearl

Faceted pearls are not your traditional cultured pearls. These avant-garde beauties can have 200+ facets on their surface. Photo: Robert Weldon/GIA. Courtesy: Victor Tuzlukov


June Birthstone: What Is a Pearl?

A pearl is an organic gem that grows inside saltwater and freshwater mollusks. These soft-bodied animals possess one (univalve) or two (bivalve) shells. Mollusks are invertebrates, meaning they lack a spine or vertebrae.

Gemologists divide the June birthstone into two categories:

  • Natural Pearls: Pearls form without human intervention. When an irritant enters a mollusk, the mollusk secretes a mixture of calcium carbonate and conchiolin (called nacre). Like a protective shell, the nacre covers the irritant. Although used for adornment for thousands of years, today natural pearls are extremely rare and make up only a small fraction of total pearl sales.
Edwardian natural pearl necklace with alternating light and dark pearls

Natural pearls are the focal point in this necklace from the Edwardian era. Photo: Robert Weldon/GIA

  • Cultured Pearls: These are a product of human intervention. Technicians implant a piece of mantle tissue alone (common for freshwater cultured pearls) or with a mother-of-pearl shell bead (all saltwater) into a host mollusk. The mollusk covers the irritant with nacre, just like a natural pearl. Cultured pearls are raised in pearl farms – saltwater or freshwater operations where the mollusks are cleaned, protected from predators and eventually harvested. Cultured pearls account for the vast majority of pearl sales.


Cultured Pearls: Akoya, Tahitian, South Sea and Freshwater

Scientists estimate there are more than 100,000 different species of mollusks in the world’s waters. However, only a few dozen of these species produce the June birthstone and only about half of them are used to produce cultured pearls. Cultured pearls are classified by the species of mollusks that produce them.

Three akoya cultured pearls

Akoya cultured pearls have an undeniable elegance. Photo: Robert Weldon/GIA

Akoya Cultured Pearls: The saltwater Pinctada fucata oyster produces white and cream-colored cultured pearls, generally between 2 and 11 mm in diameter, with the average being 6 to 8 mm. Akoya cultured pearls are often perfectly round and have a high luster (the light reflected from or near the pearl’s surface). Most akoya cultured pearls are commercially produced in Japan and China.

A necklace showing the many colors of Tahitian cultured pearls

The many different colors of Tahitian cultured pearls are on display in this exceptional necklace, which features 27 cultured pearls that range from 13 to 19 mm. Photo: Robert Weldon/GIA. Courtesy: A Private Collector and Mona Lee Nesseth, Custom Estate Jewels

Tahitian Cultured Pearls: Famous for their exotic, almost luminescent colors, these are the product of the saltwater Pinctada margaritifera oyster, which is native to the islands of French Polynesia. The mollusk produces pearls in bodycolors sometimes described in the trade with names like aubergine (dark grayish purple), pistachio (yellowish green to greenish yellow), or peacock (dark green-gray to blue-gray, with pink to purple overtones). Tahitian cultured pearls generally range from 9 to 14 mm in diameter, most commonly 9 to 11 mm.

Semi-round South Sea cultured pearl necklace with blue sapphire accents

This necklace of semi-round South Sea cultured pearls with blue sapphire accents makes a breathtaking statement. Photo: Robert Weldon/GIA. Courtesy: Atelier Marisa

South Sea Cultured Pearls: The Pinctada maxima oyster is the largest of all saltwater cultured pearl oysters, and it can produce pearls from 8 to 20 mm in diameter; the average is 13 mm. There are two types of Pinctada maxima oysters: silver-lipped and gold-lipped. The silver-lipped oyster produces pearls that are mostly white to silver, sometimes with pink, blue or green overtones. The gold-lipped oyster produces mostly yellow to orangy yellow pearls, called “gold” or “golden” in the trade.

A handful of freshwater cultured pearls in many colors

Pearls come in many colors, like these freshwater cultured pearls from China. Photo: Robert Weldon/GIA

Freshwater Cultured Pearls: From the mussel Hyriopsis cumingii or a hybrid, these pearls are produced primarily in the lakes, ponds and rivers of China. They come in many shapes, sizes (up to about 20 mm) and natural colors, including white, orange, lavender and purple. They are also dyed in a wide array of colors.

Gemologists love the June birthstone because of its luster – the reflection of light off its surface, and from concentric layers of nacre, like light bouncing off a convex mirror. Pearl’s texture also fascinates: Natural and cultured pearls have a slightly rough feeling when rubbed against your teeth, while imitation pearls are smooth. However, gemologists use X-rays to examine a pearl’s inner structure, which allows them to conclusively separate natural from cultured pearls.


June Birthstone: Pearl History and Lore

The origin of pearls fascinated our forebearers. Ancients from the Middle East believed that pearls were teardrops fallen from heaven. The Chinese fancied that the June birthstone came from the brain of a dragon. Christopher Columbus and his contemporaries thought that mollusks formed pearls from dew drops.

Pearls have long been associated with purity, humility and innocence. So it may be said that the June birthstone meaning is “sweet simplicity.” As such, pearls were traditionally given as a wedding gift.

The June birthstone was also thought to have beneficial properties. In the ancient Sanskrit text, the Atharvaveda, pearls were said to bestow long life and prosperity. In Asia, pearls were believed to help alleviate indigestion and hemorrhages. Arab physicians in the 1820s maintained that pearl powder improved eyesight, quieted nervous tremors and eased depression.

One of the most famous natural pearls is the 50.56 carat (ct) La Peregrina. About the size of a pigeon’s egg, the pearl was discovered in the 1500s in the Gulf of Panama. It became a prized possession of European royalty. Richard Burton eventually gifted it to Elizabeth Taylor in 1969; Christie’s New York auctioned it in 2011 for $11.8 million.

A two-strand necklace with 50.56 ct natural pearl pendant, accented with 56 saltwater natural pearls, four cultured pearls, rubies and diamonds

Literally a royal gem, Elizabeth Taylor’s 50.56 ct La Peregrina pearl was owned by eight Spanish kings, from Philip II (1582-1598) to Carlos IV (1778-1808). Cartier set the pearl as part of the pendant in this two-strand necklace that has 56 saltwater natural pearls, four cultured pearls, rubies and diamonds. Courtesy: Christie’s


June Birthstone: Where Pearls Come From

You’ll have to set sail for pristine waters if you want to find the June birthstone. Pearl-bearing mollusks fail to thrive in polluted waters, so pearl farms are usually located far from civilization – and often in breathtaking settings.

Saltwater pearls are grown in many areas around the world. Akoya cultured pearl farms are primarily found in Japan and China, especially along the southern coasts of Guangdong and Guangxi provinces. South Sea cultured pearls are farmed from the northern coast of Australia through Indonesia to the southern coast of Southeast Asia, with large operations in the Philippines as well. The Gambier Islands and the Tuamotu Archipelago, both part of French Polynesia, are two locales where the rich black Tahitian pearls are cultured.

An akoya cultured pearl farm in Ago Bay, Japan

Ago Bay, Japan is one of the most important sites for akoya cultured pearl farms. Photo: Valerie Power/GIA

Freshwater cultured pearls are primarily grown in China, within a 400 mile (644 km) radius of Shanghai.

A cultured pearl farm in French Polynesia

The breeding waters of a cultured pearl farm in French Polynesia look like a piece of paradise. Photo: Amanda Luke/GIA

Natural pearls have been found in the Arabian Gulf (Persian Gulf) for at least 5,000 years, while divers have been recovering the June birthstone from the Red Sea since 300 BCE. The Strait of Mannar has been providing pearls since 2000 BCE. Starting in the 16th century, during Spanish colonial rule, large quantities of pearls were recovered from the waters off Mexico, Central America and what is now Venezuela. Only small quantities of pearls are found in any of these areas today.


June Birthstone: Pearl Qualities to Look For

As you’re shopping for pearls and comparing quality and prices, keep in mind the seven factors gemologists use to evaluate and describe the quality of the June birthstone. Known as the GIA 7 Pearl Value FactorsTM, they are:

  1. Size: Pearl measurements are stated in millimeters, rounded to the nearest 0.5 mm. All things being equal, the larger the pearl, the greater its value.
  2. Shape: GIA categorizes pearls as one of seven shapes:
    • Round
    • Near-round (almost round, with minor variations)
    • Oval
    • Button (symmetrical, circular and flattened)
    • Drop (symmetrical, rounded or pear shaped)
    • Semi-baroque (not quite symmetrical; an off-round)
    • Baroque (has no apparent symmetry and is noticeably irregular)
  3. Color: Pearl color has three components:
    • Bodycolor – The dominant, overall color of the pearl
    • Overtone – A translucent color that appears to layer over a large area of the pearl’s surface
    • Orient – More than one translucent color over the bodycolor, or surface iridescence
  4. Luster: The intensity and sharpness of the light reflected from a pearl’s surface. There are five categories of luster: excellent, very good, good, fair and poor.
  5. Surface: The nature and number of blemishes or irregularities on the pearl. As products of nature, few pearls are completely blemish free. Pearl surface is described as clean, lightly spotted, moderately spotted, or heavily spotted.
  6. Nacre Quality: The thickness and regularity of the nacre. For nacre quality to be acceptable on a bead-nucleated cultured pearl, no evidence of the bead should be visible and there should be no chalkiness.
  7. Matching: This factor applies when evaluating a strand of pearls or a jewelry item with two or more pearls. Excellent matching requires a uniform appearance across all the pearls, with the drill hole on center.

You should also know that cultured pearls routinely undergo treatment to improve their appearance. Some may be color enhanced by heating, dyeing, irradiation and coating. Other treatments include:

  • Bleaching – To whiten them and create a uniform appearance
  • Tinting – The use of a red dye to turn akoya cultured pearls pink (also called pinking)
  • Buffing – Tumbling pearls in a canister (or similar device) to remove surface imperfections
Diamond and Tahitian cultured pearl cluster earrings

Take special care when cleaning pearl jewelry like these diamond and Tahitian cultured pearl earrings. Photo: Robert Weldon/GIA. Courtesy: Mastoloni, New York


June Birthstone: Pearl Care and Cleaning

Pearls are 2.5 to 3.0 on the Mohs Scale of hardness, so they are a comparatively soft gem and require special care. Store them separately from other gemstones and metal jewelry to prevent scratching. Never store pearls in a plastic bag — plastic can emit a chemical that will damage their surface. Always apply perfume, hair products and cosmetics before putting on your pearl jewelry. The best way to clean your June birthstone: Use a soft, damp cloth, ideally after each time they are worn.

Read more tips on how to care for pearl jewelry to keep your watery treasures beautiful.

June is a month for celebrations, be it weddings, anniversaries, graduations or birthdays. And what better way to celebrate than with the June birthstone. From a classic strand of akoya cultured pearls to a single faceted Tahitian cultured pearl, there’s a look for every taste and budget.

Pearls are trending. Five Easy Pieces shows how to wear them with style.

May Birthstone: What You Need to Know About Emerald

With spring in full bloom and summer just around the corner, emerald is the perfect choice for the May birthstone. Kings and queens have prized the sought-after green gem for centuries. Here’s how you can pick a breathtaking one.

In this post, we cover:
Gemological Qualities of Emerald
Emerald History & Lore
Where Emerald Comes From
Emerald Qualities to Look For
Emerald Care & Cleaning


May Birthstone: Gemological Qualities of Emerald

Emerald’s green has been the standard by which other green gemstones have been measured for thousands of years. It is the rich green to bluish green variety of beryl, a mineral species that also includes aquamarine and varieties in other colors.

Trace elements that cause emerald’s color include chromium, vanadium and iron. As a general rule, the higher the chromium or vanadium content, the more intense the green color. The more iron present, the greater the degree of blue. When iron content is relatively high, emerald is a bluer green. When iron content is relatively low, the May birthstone is a purer green.

The difference between an emerald and a less-expensive green beryl is a matter of debate among gem experts. Some in the trade describe the May birthstone as any green beryl colored by chromium. However, gemologists, gemological laboratories and most colored stone dealers, think it is incorrect to call a green beryl an emerald when its color is “too light.” There are differences of opinion even in this group about the definition of “too light.” GIA settles the debate by using lab-graded comparison stones to determine if the green color is sufficiently dark and saturated to be called emerald.

Gemologists love the May birthstone for its inclusions. Emeralds from Colombia can have fascinating characteristic inclusions – called three-phase inclusions – that consist of tiny crystals of rock salt, a liquid and a bubble of gas.

The best emerald crystals are also gorgeous flat-topped green hexagonal columns that can rival the beauty of faceted stones.

A 47 carat rough emerald crystal

Weighing in at 47 carats, this rough emerald crystal from the Muzo mine in Colombia is so beautiful that it may put to rest all debates about color. Photo: Robert Weldon/GIA. Courtesy: Jon Sigerman


May Birthstone: Emerald History & Lore

From Egyptian pharaohs to Inca emperors, emerald has enchanted royalty. Cleopatra was known to have a passion for emerald, and used it in her royal adornments. The legendary Crown of the Andes, fashioned in colonial South America, is one example of how the Spanish revered the May birthstone. According to lore, its largest stone—now called the Atahualpa emerald—was taken from the last Inca emperor, Atahualpa, by conquistador Francisco Pizarro. The modern recovery of the Spanish galleon Nuestra Señora de Atocha shows the length generations of treasure hunters would go to recover its sunken loot.

The word “emerald” comes from smaragdos, ancient Greek for a green gem. Roman author Pliny the Elder, who died in the 79 CE eruption of Mt. Vesuvius, wrote in his encyclopedic Natural History that “nothing greens greener.” He also stated that the May birthstone had therapeutic properties that helped gem cutters: “(they) have no better method of restoring their eyes than by looking at the emerald, its soft, green color comforting and removing their weariness and lassitude.” Science now proves this belief: The color green relieves stress and eye strain.

An emerald and diamond necklace totaling 41.97 carats

An emerald necklace sure to soothe the eye, this beauty has 52 emeralds, with a total weight of 32.86 carats, and 160 diamonds, with a total weight of 9.11 carats. Photo: Robert Weldon/GIA. Courtesy: Ismael Daoud

Emerald was also thought to have magical powers. By placing it under the tongue, one could see into the future. Some believed the May birthstone offered protection against evil spells, cholera and malaria. Others thought it made one an eloquent speaker and exposed lovers who made false promises.

Emerald is traditionally given for the 20th and 35th wedding anniversaries.

The Crown of the Andes is set with a 24 ct emerald center and 442 additional emeralds

The Crown of the Andes, now at the Metropolitan Museum of Art in New York City, boasts an impressive 24 ct emerald center stone and 442 additional emeralds set in the golden headpiece. Photo: Dr. E. J. Gübelin/GIA


May Birthstone: Where Emerald Comes From

Colombia has been the source of the finest emeralds for more than 500 years, and they have been the standard by which all others are measured. Three mining sites in Colombia are particularly noteworthy: Muzo, Chivor and Coscuez. Emeralds of slightly different hues are found at each of these sites. Each locality produces a range of colors, but generally speaking, darker tones of pure green emeralds come from Muzo. Emeralds that are lighter in tone and slightly bluish green are associated with Chivor. Slightly yellowish green emeralds are unearthed in Coscuez.

A 38 carat emerald crystal cluster

This 38 carat cluster of emerald crystals originated from Colombia’s Muzo Mine. Photo: Robert Weldon/GIA. Courtesy: Ismael Daoud

A 4.50 ct polished emerald

Chivor, Colombia is the source of this 4.50 ct emerald. Photo: Robert Weldon/GIA


An 88.4 gram emerald crystal cluster

This 88.4 gram emerald crystal cluster is from Coscuez, Colombia. Photo: Robert Weldon/GIA. Courtesy: Gene Meieran

Emeralds are also found in the state of Minas Gerais, Brazil. One of the most productive sites for the May birthstone is the sophisticated Belmont Mine. Capoeirana is another important locality, a rugged region worked largely by independent miners and small-scale operations.

An independent miner holds a rough emerald

An independent miner at the Capoeirana mining area holds a rough emerald. Photo: Eric Welch/GIA

The May birthstone can also be found in Africa. Zambia is a major source, and mines in the Ndola Rural Restricted Area are known for producing emeralds that are bluish green and darker in tone. Pakistan and Afghanistan are important producers as well.

A 240 carat emerald drop necklace

The 240 carats of emeralds in this drop necklace come from Zambia. Photo: Robert Weldon/GIA. Courtesy: Sanjay Chordia, BEACAB GEMS INC.


May Birthstone: Emerald Qualities to Look For

Color: The most important quality factor in the May birthstone is color. Emeralds that are bluish green to green, with strong to vivid saturation and medium to medium-dark tone, are the most coveted. Emeralds that are highly transparent are especially valuable.

Clarity: Emeralds typically contain inclusions that are visible to the unaided eye. Because of this, jewelry professionals and some consumers understand and accept the presence of inclusions in emeralds. Eye-clean emeralds are especially valuable because they’re so rare.

Emerald inclusions are often described as looking mossy or garden-like. They’re sometimes called jardin, which is French for “garden.”

In colored stones, transparency and clarity are closely linked. This is especially true for emeralds. Jewelry professionals generally accept some eye-visible inclusions in higher-quality emeralds. But when the quantity or nature of the inclusions has a negative effect on transparency and clarity, they also dramatically reduce value.

Cut: Emerald crystals are difficult to cut. Almost all rough emeralds have significant fractures (sometimes called fissures) and a gem cutter must work to minimize the effect of those fractures on the appearance of the finished stone.

These inherent fissures make emeralds more brittle than other gems. Consequently, they are vulnerable to damage during cutting, polishing and setting–or even from careless daily wear.
The famous rectangular “emerald cut,” with its beveled corners and two, three or four concentric rows of facets, maximizes the shape and weight of the original emerald crystal. It also helps protect against damage because the vulnerable corners are faceted and provide a comparatively safe place for prongs.

Carat Weight: Fashioned emeralds come in a wide range of sizes. There are emeralds in museums and private collections that weigh hundreds of carats. At the other extreme are tiny emeralds that weigh fractions of a carat.

A 3.69 ct emerald ring with six diamond side stones

Take extra caution when caring and cleaning for emerald jewelry like this 3.69 ct emerald ring flanked with six diamond side stones. Photo: Robert Weldon/GIA. Courtesy: Ismael Daoud


May Birthstone: Emerald Care & Cleaning

Emerald is a 7.5 to 8 on the Mohs scale of hardness, so it is more susceptible to scratching than a diamond, which ranks 10 on the scale. The May birthstone is often treated to improve its color and clarity. Common treatment methods include:

  1. Dyeing: Paler porous or fractured emeralds are dyed green to enhance their color.
  2. Fracture Filling: Oils, waxes and artificial resins are sometimes used to fill surface-reaching fractures in emeralds. The goal is to reduce the visibility of the fractures and improve the apparent clarity. The volume of filler material present can range from insignificant to major; these substances have varying degrees of stability.

Emerald requires some special care; avoid exposure to heat, changes in air pressure (such as in an airline cabin) and harsh chemicals. Never put an emerald in an ultrasonic cleaner. Filled emeralds can also be damaged by exposure to hot water used for washing dishes.

The May birthstone is perfectly suited to the celebration of life blooming everywhere. Now you can treat yourself – or a loved one – to an emerald that captures the exuberance of the season. Learn more about how to pick a beautiful emerald with our Emerald Buying Guide.

GIA Holiday Shopping Guide: How to Choose A Birthstone for the Perfect Holiday Gift

Stunning, striking, and simply gorgeous, birthstone jewelry is a great holiday gift. Show your affection with a gift that merges individuality with style. A birthstone celebrates her personal story and represents a bit of who she is, so you may want to start the process by asking yourself what style suits her. Is she traditional or contemporary, classic or colorful? Does she prefer her metal silver spun or in a golden twist? Once you’ve got her design preferences down, don’t forget the qualities that make a birthstone valuable. (more…)

17.96 ct, aquamarine
Aquamarine Buying Guide

March’s aptly titled birthstone, aquamarine, grows in gorgeous crystals and sparkles like the ocean on a sun-kissed day. But do you know what to look for when shopping for aquamarine? (more…)

amethyst stone
Amethyst Buying Guide

Known for its majestic purple color, amethyst is the gemstone of choice for those born in February. (more…)

Fire opal gemstone
Red Gemstone Buying Guide – Part 2

As passions ignite this month, a jewelry gift featuring a red gemstone is a token of love that can be enjoyed every day. While seen mostly in fashion jewelry, red gemstones are showing up as an option for the primary stone in engagement rings. Celebrities like Jessica Simpson, who sports a 5-carat ruby engagement ring, have been influential in bringing gemstones to the forefront of bridal trends. In addition to rubies, garnets and red diamonds, which we discussed yesterday, the following gemstones are more options for those looking to celebrate this Valentine’s Day with a gift of a spectacular red gem. (more…)