Those celebrating December birthdays are fortunate to have a few birthstones to choose from – zircon, tanzanite, blue topaz and lapis lazuli, among them. But one of the best known and most loved December gems is turquoise, a gem that has been mined and used for thousands of years.

Jewelry found in ancient Egyptian tombs dating to 5500 BCE give turquoise the distinction of being one of the longest-loved gems in history. Many in the U.S. associate turquoise with Native American jewelry, but the gem is also commonly found in China and beloved by designers and collectors around the world.

One of the reasons collectors love this gem is because its appearance can have so much variation. Not all turquoise is turquoise! Turquoise is colored by copper, which creates an array of colors from intense blue to greenish blue to avocado and lime green. The gem’s color can be an evenly distributed medium blue, appear mottled, or display matrix. Matrix is the remnant of the host rock in which the turquoise formed and appears as splotches or veins.

The most prized turquoise color is an even, vibrant blue sometimes called “Persian blue” in the trade, as seen on the right. The stone on the left shows a wonderful example of matrix veins referred to as spiderweb turquoise

Turquoise is most often cut into cabochons, smooth domed shapes that are best suited to show off the stone’s color and any matrix. However, designers also use turquoise in jewelry inlays, as seen in this ring.

This white gold ring by Andrew Sarosi, set with diamonds and turquoise from the Sleeping Beauty mine in Arizona, shows the versatility of turquoise as the backdrop for the diamond detail. Image courtesy of Andrew Sarosi, L.A., Ca.

Turquoise rough is also fashioned into round or oblong beads or tumbled into “nuggets”.

This one-of-a-kind multi-strand necklace of turquoise and gold nuggets, created by Denise James, shows a more unusual use of turquoise in its rough form. Courtesy Denise James.

If you own (or hope to own) turquoise jewelry, there are a few things to keep in mind. Natural turquoise is porous, and its porosity makes it a candidate for treatment to alter its color and improve its durability. The gem can be discolored by chemicals, perfume, cosmetics, and even natural skin oils, so remove turquoise jewelry when cleaning or applying products to your skin.

When needed, clean turquoise with warm, soapy water; never use steam or ultrasonic cleaners. More on the care and cleaning of turquoise can be found on our Gem encyclopedia.

With the right care, fine-quality turquoise is quite durable, and jewelry fashioned from the gem will last generations.

Do you have a December birthday? You actually have a choice of birthstones: do you prefer the unique look of turquoise, the fire of zircon, or the lovely rich-hued tanzanite?

**White gold Sleeping Beauty turquoise earrings in main image courtesy of Andrew Sarosi, L.A., Ca.

The post Turquoise: December’s Birthstone, Loved for its Sky Blue Color appeared first on GIA 4Cs Blog.

As the majority of the country heads into cooler temperatures of late fall/early winter, November’s birthstone, citrine, provides a much needed burst of sunshine. The warm, sunny color of this popular gemstone inspired its name, derived from the French word “citron,” meaning “lemon.” Its color ranges from saturated yellow to  reddish orange to pale  yellow.

Citrine is part of the mineral  species quartz, along with sibling gemstones amethyst, rose quartz, smoky quartz, rock crystal quartz and tiger’s-eye quartz. Much of the citrine on the market today is actually amethyst that has been heat-treated to turn it  yellow. Occasionally, you will hear citrine referred to as topaz; however, topaz  is a different mineral.. Both citrine and topaz are birthstones for November, and the colors of  yellow topaz and citrine can easily be confused.

A 214.91 ct citrine, cut by Michael Dyber.

Like all quartz gems, citrine is readily available and affordable, including very large-size stones.

The warm hue of citrine is commonly paired with polished, yellow gold, as seen here:

Inspired by the stars and the cosmos, this “Pluto” ring has two citrines set in gold. Gift of Patricia MB Gotthif.

Its sunny color is also a bright addition to multi-colored designs, and can be frequently found in a bouquet of gems including amethyst, topaz, peridot, and tourmaline.

Group of five cut citrines. Ranging in color from yellow, orange and brown.

Most citrine is mined in Brazil, especially from the state of Rio Grande do Sul. However, large amounts of amethyst and citrine have also been found in the Anahí mine in Bolivia, as well as Africa.

With a hardness rating of 7 on the Mohs scale, and good toughness, citrine is durable and will hold up to everyday wear.  However, high heat can cause color loss so you do not want to expose it to sunlight for extended periods of time. Cleaning is simple; just use a mild dish soap and warm water.  It’s an easy-to-care-for, affordable, and distinctive gemstone, making it popular for those with November birthdays (and many others as well).

Suite of citrines. (C) ICA

Do you have a birthday this month? Do you think citrine looks best standing alone, or do you prefer it paired with other gems to create a multi-colored look?

*At top Cartier citrine and diamond bracelet. (C) GIA & Tino Hammid

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The October birthstone, opal, is noted for its individuality, magic, and mystery. Its unique display of flashing rainbow colors is unlike any other gem, and has been compared to volcanoes, galaxies, and fireworks.

Throughout history, its intense visual qualities have made it a source of supernatural beliefs.  Bedouins believed that opals contained lightning and fell from the sky during thunderstorms. Ancient Greeks believed opals guarded them from disease. They’ve even been attributed with the power to preserve blond hair!

An opal’s value is determined in part by its background  color. A darker base with vivid flashes of color is the most desirable, and opals with dark gray to black base color are the most valuable. One famous black opal is the 700 carat stone Napoleon gave his wife and Empress Josephine de Meauharnais called “The Burning of Troy” because of its red flashes against a black  background color.  A more  affordable type of  opal has a white  to medium gray background color, called white opal.

Black opals, like this 29.85 carat gemstone from Australia, are prized for their rarity and fiery color. Courtesy of Mariora, Surfers Paradise, Australia

Another key factor in determining an this gemstone’s value is the amount and distribution of flashing rainbow colors, called play-of-color. Play-of-color occurs because of the interaction of light with its internal structure. This causes light waves to diffract, or bend, resulting in spectral colors that range from , red, orange, yellow, green, and blue. There are two broad classes of opal: precious and common. Precious opal displays play-of-color, common opal does not.

“The Path of Enlightenment” necklace contains 180 opals, and is an excellent example of the vast spectrum of colors found in opals. Courtesy of Impressions Ltd.

These gemstones are some times treated to improve their color. Synthetic opal, created in the 1970’s is available in black, white, and fire opal. You may also run across imitation opals made out of glass (called Slocum Stone) and plastic.

If you’re the fortunate owner of a precious opal, the best way to care for it is with warm, soapy water. Ultrasonic cleaning or steam cleaning are never recommended for this fairly delicate gemstone. With a hardness of 5-6.5 on the Mohs scale, it is softer than many gems and should be treated with care.

Opal salamander pin (bottom). (C) GIA and Tino Hammid. Courtesy of Neil Lane, Inc.; Beverly Hills, California.

How would you describe the play-of-color found in opals–flashing rainbow, volcano, galaxy, fireworks? Use your imagination to come up with a way to describe this unique phenomenon.

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Think of every passing year as an opportunity to celebrate with your birthstone. In fact, people have been wearing birthstone jewelry since the 15^th century in Poland, when they were encouraged to own all 12. And while birthstone secrets and lore can be found right here on our blog, today we share what makes YOUR birthstone a powerful statement of your finest qualities.

The post Discover the Powers of Your Birthstone appeared first on GIA 4Cs Blog.

August’s fascinating birthstone may be called the “extreme gem” because it is formed in the most extreme conditions, found in lava, meteorites and deep within Earth’s mantle. Peridot has been found in pallasite meteorites, which contain remnants of our solar system’s birth. In 2006, peridot was found in comet dust brought back from the Stardust robotic space probe.

“The Green Goddess”, 154 carat peridot set in gold with yellow diamonds accents. Image courtesy of The Field Museum.

However, as exciting as extraterrestrial peridot is, it is more commonly found here on Earth, particularly in volcanic rocks known as basalts. The gemstone can commonly be found in lava flows in the United States, China and Vietnam. Sometimes peridot can be found as large crystals lining veins or pockets in certain types of solidified molten rock in Finland, Pakistan and Myanmar.

Peridot from Ethiopia. Image (c) ICA.

Throughout history, peridot has often been confused with other gems such as topaz and emerald. The Shrine of the Three Holy Kings in Germany’s Cologne Cathedral is decorated with 200 carats of gems. They were believed to be emeralds, but they are , in fact, peridots. Some historians even speculate Cleopatra’s famous emerald collection may have been comprised of peridot.

6.33carat peridot pendant set in 18k white gold.

Peridot is the gem variety of the mineral forsterite , which contains iron and magnesium. It is part of the mineral group olivine and ranges from yellowish green to greenish yellow. Peridot’s finest color is a richly saturated green to slightly yellowish-green that’s free of brownish tints.Smaller, lighter shades are widely available and more affordable. A well cut peridot can be a beautiful and brilliant gem.

Peridot with rich, deep yellow green color.

Peridot is softer than many gems with a hardness of 6.5 to 7 on the Mohs scale. Peridot should be stored with care to avoid scratching. It can be cleaned with mild dish soap in warm water using a toothbrush to scrub behind the stone where dust can collect. Ultrasonic and steam cleaning are not advised, as either of these methods risks damaging the stone.

Are you an August baby or do you just love peridot? Please share what makes peridot special to you!

The post Peridot: The Extreme Gem appeared first on GIA 4Cs Blog.

The legendary beauty of June’s luminescent birthstone has been celebrated for centuries. We explored the pearl’s history and lore, the various types of pearls available, and how a pearl’s value is assessed and what to look for when purchasing a pearl. Now we are going to discuss how to care for one!

Pearls are one of the more delicate gemstones, so they require extra care. Avoid wearing pearls when cleaning the house or doing yard work to avoid scratching. Chemicals contained in perfume and the ingredients in makeup and hairspray can eat away a pearl’s nacre, causing it to dull permanently. Cleaning products containing chemicals such as ammonia and chlorine should also to be avoided, so don’t ever wear your pearls in the pool!

Pearls need a certain amount of moisture to retain their beauty, so avoid storing them in airtight or overly dry environments. Luckily, the human body provides just the right amount of moisture to maintain a pearl’s effervescent luster. Pearls are made to be worn and enjoyed!

Here are some more great tips to help keep your pearls as beautiful 50 years from now as they are today.

• The best way to clean pearls is with a soft, damp cloth, ideally after each time they are worn.
• Pearls should never be cleaned in an ultrasonic or steam cleaner. Warm soapy water is safe, assuming the nacre is in good condition. Make sure strung pearls are completely dry before wearing.
• Store pearls separately from gemstones and metal jewelry, which may scratch their surface.
• Never store your pearls in a plastic bag. Plastic can emit a chemical that will damage the surface of pearls. The same is true of cotton wool.
• Don’t store pearls in a safe deposit box for long periods of time. Like your skin, pearls need a little moisture so that they will not dry out.
• Always apply perfume, hair products and cosmetics before putting on your pearl jewelry.
• A good rule of thumb is: when dressing, pearls should be the last thing you put on and the first thing you take off.

We hope you’ve enjoyed learning about pearl care. If you are looking for more information on these spectacular gemstones, you will enjoy our new book ‘Splendour & Science of Pearls‘.

The post Caring for June’s Birthstone: Pearls Part 4 appeared first on GIA 4Cs Blog.

Celebrated for its mesmerizing beauty, the Grace Kelly of gems is June’s elegant birthstone–the pearl. We previously discussed the pearl’s history and lore, and the different types of pearls. Now let’s delve into how a pearl’s value is assessed, and what to look for when purchasing a pearl.

Though most known for creating the 4Cs and diamond grading standards, GIA also created a standard for describing pearl quality – the GIA 7 Pearl Value Factors™. These factors are:

1.    Size: Measured in millimeters,  and rounded to the nearest 0.5 mm

2.    Shape: Described as Round, Near-round, Oval, Button, Drop, Semi-baroque and Baroque

3.    Color: A combination of the pearl’s dominant body color, overtone and orient. Body color takes into account hue, tone and saturation. Overtone is a noticeable translucent color that appears to layer over the pearl’s body color. Orien
t is the mixture of colors shimmering just below the pearl’s surface.

4.    Luster: The light reflected from the pearl’s surface, evaluated by the intensity and sharpness of the reflection. Luster is evaluated according to the following scale:

• Excellent – reflections appear bright and sharp
• Very Good – reflections appear bright and near sharp
• Good – reflections are bright, but not sharp
• Fair – reflections are weak and blurred
• Poor – reflections are dim and diffused

5.    Surface: Evaluated based on the blemishes or irregularities in the pearl’s surface, taking into account the size, number, nature, location, visibility and type of surface characteristics. Surface is rated by the following scale:

• Clean – blemish-free, or containing minute surface irregularities that are difficult to see
• Lightly spotted – only minor surface irregularities are visible
• Moderately spotted – noticeable surface blemishes
• Heavily spotted – obvious surface irregularities that might affect durability

6.    Nacre Quality: Nacre quality is determined by its thickness and layering. hen the thickness of the nacre coating on a bead cultured pearl is too thin or damaged, appears chalky, or if the bead can be seen through the nacre, it may impact the pearl’s ability to sustain normal wear.

• Acceptable – nucleus not noticeable; no chalky appearance
• Nucleus visible – pearl(s) show evidence of bead nucleus through the nacre
• Chalky appearance – pearls have an obvious dull appearance

7.    Matching: This measurement only applies to a strand of pearls, or jewelry pieces with multiple pearls, by assessing the uniformity of all the pearls in the piece.

• Excellent – uniform in appearance and drilled on-center
• Very good – very minor variations in uniformity
• Good – minor variations in uniformity
• Fair – noticeable variations in uniformity
• Poor – very noticeable variations in uniformity

Pearls are often treated to improve color, shape, surface appearance, weight and durability. Pearls are porous, which allows them to accept many treatments more readily than non-porous gemstones, while their softness permits them to be shaped fairly easily. Treatment processes may include bleaching, heating, dyeing, irradiation and coating to improve color; peeling to improve shape and or surface appearance; or filling and impregnation to increase weight or enhance durability.

So how can you be sure about the quality of pearls you’re buying? GIA Pearl Reports provide in-depth information about detectable treatments, the pearl’s origin, its growing environment and the mollusk species that produced it. The report includes a quality description based on the GIA 7 value factors described above.

Please join us for the final installment of our June birthstone blog series where we’ll share valuable tips on how to care for your pearls!

Does learning about these factors help simplify your decision-making process? We’d love to hear from you!

The post 7 Factors Describe June’s Birthstone: Pearls Part 3 appeared first on GIA 4Cs Blog.

June’s lustrous birthstone is celebrated around the globe for its compelling beauty. Earlier this week we discussed the source and history of the pearl. Today we’ll be diving into the various types of pearls.

Natural saltwater pearls are extremely rare and valuable. They are most often found in the Arabian Gulf (or Persian Gulf), where 70-80 percent of all natural pearls were discovered until the 1930s. Natural pearls can also be found in, the Red Sea and Strait of Manaar. Occasionally, natural saltwater pearls are unearthed in Baja California, Venezuela, Myanmar, China, Japan, India, French Polynesia, Australia and Africa – the same regions that have cultured pearl industries.

The majority of pearls on the market are cultured pearls. Cultured pearls are formed with human assistance under controlled conditions in pearl farms around the world. Technicians insert a bead or piece of tissue into a living mollusk, and the mollusk responds by depositing layers of nacre over the irritant, which over time gives rise to a miraculous pearl.. Cultured pearls fall into four types :

Akoya
• Environment: Saltwater
• Colors: White or cream with yellow, pink or blue hues and overtones of pink or green
• Size: Typical size range is 6 mm to 7 mm. You may see them as small as 2 mm and as large as 10 mm

Tahitian
• Environment: Saltwater
• Colors: Black, gray, silver, brown. Overtone colors can include blue to green, purple, yellowish green and pink.
• Size: Typical size range if 8 mm to 14 mm

South Sea
• Environment: Saltwater
• Colors: White, cream or silver, with yellow, orangy yellow or blue hues and overtones of pink, green or blue
• Size: Usually 15 mm and larger but can be smaller

Freshwater
• Environment: Freshwater, usually cultured in lakes and ponds
• Colors: white or cream with yellow, orange, pink or purple hues and overtones of pink, blue or green
• Size: Typical size range is 4 mm to 14 mm

Different environments and different mollusks produce different types of pearls, which makes cultured pearls a fascinating enterprise. Next up in our June birthstone series, we’ll provide some insight into how pearls are graded and their value is determined.

Do you have a favorite type of pearl or pearl color? Please share!

The post The Varieties of June’s Birthstone: Pearls Part 2 appeared first on GIA 4Cs Blog.

The luminous pearl is June’s coveted birthstone. This enchanting treasure originating from the sea is a timeless wardrobe staple, beloved by fashion icons including Audrey Hepburn and Coco Chanel. In this four-part series, we’ll be (1) sharing the source and history of pearls, (2) exploring different pearl varieties, (3) assessing factors behind pearl value, and (4) learning about how to care for your pearls.

A black-lipped oyster, which produces the Tahitian pearl.

Pearls are organic gems that form inside the tissue of a living mollusk (either an oyster or a mussel). The mollusk secretes a substance called nacre when an irritant such as a piece of sand or a parasite invades its shell. The mollusk continues to secrete layers of nacre, until the nacre-covered speck becomes a pearl. This process usually spans the course of two years.

Isla Margarita pearls. Image courtesy of KCB Natural Pearls.

Pearls come in an abundance of sizes, colors and shapes, which are determined by the unique conditions in which they form. Natural pearls are rare; cultured pearls are divided into freshwater and saltwater varieties in controlled pearl farms around the world. Cultured pearls are formed by inserting a bead or a piece of mantle tissue into the mollusk. It is estimated there are approximately 100,000 species of mollusk, but only 14 are used to produce cultured pearls.

This 450-carat, natural baroque freshwater pearl was once owned by Philip Henry Hope. © Christie’s Images / The Bridgeman Art Library.

The pearl has been beloved by royals throughout history. Queen Elizabeth the First is adorned with huge pearls in many of her portraits. Cleopatra was said to have two of the largest pearls in the world in her possession. Legend has it that she dissolved and drank one of them at the world’s most expensive banquet. The other pearl was cut into two pieces and placed in the ears of Venus in the Pantheon at Rome.

There is more to learn about pearl lore, as well as interesting facts on our Gem Encyclopedia pages.

Don’t forget to tune into the next segment of our June birthstone series, where we take a deeper look at the various types of cultured pearls!

There are many influential celebrities and historical figures who have donned pearls through the ages! Who is your favorite pearl jewelry icon and why?

The post The History & Lore of June’s Birthstone: Pearls Part 1 appeared first on GIA 4Cs Blog.

This stunning green gem gets its name, from the ancient Greek word “smaragdos,” meaning “green stone,” and helps to celebrate those born in May as well as 20th and 35th wedding anniversaries. Its lush green hue has soothed souls and excited imaginations since ancient times, and in 2013 emerald green is the designated “Color of the Year”.

24.72 carat emerald pendant.

Emerald is the bluish green to green variety of beryl, a mineral that also includes aquamarine. Mined for thousands of years, this gemstone has adorned the elite of ancient civilizations and have been credited with magical powers. This gemstone was thought to be a protection against evil spells and a cure for diseases such as cholera and malaria. Wearing an emerald was believed to reveal the truth or falseness of a lover’s oath as well as make one an eloquent speaker.

6.92 carat emerald ring.

Emerald has many special qualities, they are most of all about color. Subtle variations in color make significant differences in value. Another important factor in determining an emerald’s value is the location from which it is mined. Countries like Colombia, Brazil, Zimbabwe and Zambia supply the majority of the world’s emeralds.

Emeralds typically contain inclusions that are visible to the unaided eye. Because of this, trade professionals and some consumers understand and accept the presence of inclusions in emeralds. Emerald inclusions are often described as looking mossy or garden-like, and are sometimes called “jardin,” which is French for garden.

Van Cleef & Arpels “Fruit Salad” bracelet with emerald beads, sapphire and ruby leaves with marquise diamonds.

Emerald is a durable gem with a hardness of 7.5 to 8 on the Mohs scale, making it great for everyday wear. Although ultrasonic cleaning and steam cleaning are not safe options for emerald jewelry, you can clean them with room temperature soapy water. In order to preserve these unique green gems, we recommend cleaning gently, avoiding any vigorous scrubbing. Use a toothbrush to gently remove dust that has collected behind the stone. Emeralds with inclusions should be treated with proper care and be protected from blows.

16-strand emerald necklace.

For all the emerald lovers out there, share your favorite emerald looks!

The post Emerald Birthstones: The secret power of a green gemstone appeared first on GIA 4Cs Blog.