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What Is a Real Diamond?

January 10, 2017

What Is a Real Diamond?

It’s unlikely that you’ll hear a professionally trained gemologist call a diamond a real diamond, or use the word “real” to describe any material. If you want to come across as a smart shopper, you’ll need to rephrase the question.

For decades, diamonds have been the gem of choice for engagement rings. But with the advent of synthetic diamonds and diamond simulants, it’s only natural to ask about real diamonds. “Real” is not a gemological term. But to the consumer, it’s an important one.

A Diamond Is a Diamond Is a Diamond

From a gem professional’s point of view, a diamond is a diamond if it has a characteristic chemical composition and crystal structure. Diamond is composed almost entirely of a single element: carbon. It forms under conditions of high temperature and pressure that cause its carbon atoms to bond in essentially the same way in all directions. Another mineral, graphite, also contains only carbon, but its formation process and crystal structure are very different. The result is that graphite is so soft that you can write with it, while diamond is so hard that you can only scratch it with another diamond.

This definition of diamond applies to diamonds that come from the earth, as well as those that are created in a laboratory. It does not apply to other materials that might masquerade as diamonds.

So, when you ask a jeweler for a real diamond, you could be asking for a diamond created by nature or one created in a lab – since both materials qualify as diamond. Reputable jewelers avoid the term “real” altogether and, following U.S. Federal Trade Commission (FTC) guidelines, clearly distinguish between natural diamonds, synthetic diamonds and diamond simulants (or imitations).

In other posts we explain synthetic diamonds and diamond imitations. Here, we’ll dig a little deeper into natural diamonds and their incredible journey from deep below the earth’s surface to the engagement ring worn by your loved one.

A Brief Description of a Natural Diamond

Natural diamonds are one of nature’s wonders. Billions of years old, they formed deep in the earth’s mantle and were brought to the surface by volcanic eruptions. Two types of magma, kimberlite and lamproite, sometimes carried diamond rough with them. The magma quickly solidified into a diamond-bearing kimberlite or lamproite pipe.

A craton is an ancient, deep and stable portion of a continent. Its high heat and pressure provide the right conditions for diamond formation. Conditions under a craton are also stable enough to preserve diamonds for hundreds of millions of years after formation. Illustration: Peter Johnston/GIA

Most of the world’s diamonds are found in kimberlite, but the famed Argyle mine in Australia–once the world’s leading diamond producer– is a lamproite deposit. Major companies recover the diamonds by digging large open-pit mines to find the buried treasures. Over time, as the typically cone-shaped pipes narrow down, the companies switch to underground mining to capture the last of the diamonds.

Some diamonds end up in rivers, streams and even the ocean after forces of erosion released the crystals from their host rocks and gradually washed them into bodies of water. When diamonds are found this way, it’s called alluvial mining – a process of digging and sifting through mud, sand and gravel. While river sediments are often worked by small-scale miners using rudimentary techniques, large boats are used to scour the ocean sands off the coast of Namibia in search of fine diamonds.

A natural diamond rough in an octahedron shape.

Natural diamond rough is often shaped like an octahedron. Photo: Robert Weldon/GIA. Courtesy: Fusion Alternatives

For most of recorded history, the extreme scarcity of diamonds made them available only to the elite. In fact, up until 1730, the Golconda region of southern India and the Pacific island of Borneo were the only known diamond-producing regions in the world. Then diamonds were discovered in Brazil around the 1720s and a diamond ‘rush’ began. Soon, Brazil eclipsed India as the world’s top diamond producer, holding this title through the mid-1800s. With the discovery of large diamond-bearing kimberlite pipes in South Africa in the late 1860s, mining began on an industrial scale, increasing supply to meet broader consumer demand. Diamonds are now mined in several countries around the world, including Russia, Botswana and Canada, as well as South Africa and Australia. Learn more about where diamonds come from.

The face-up view of this diamond showcases the beauty of the round brilliant cut. Photo: Robert Weldon/GIA. Courtesy: Rogel & Col, Inc.

Turning Rough Diamonds into Polished Gems

The diamonds recovered have survived a brutal birth and then a rough ride to the earth’s surface. Diamond mining companies must remove a million parts of host rock to find one rough diamond. Workers then sort the rough diamonds into categories based on their size, shape, clarity and color. The mining company might cut a finished diamond out of the rough, or sell it to dealers and manufacturers.

Rough diamonds are often shipped to cutting centers in India, Israel, New York, Antwerp, China and Thailand. Highly skilled diamond cutters often use the latest technology, such as lasers, to transform the piece of rough into a highly polished faceted diamond. Most finished diamonds are sent to grading laboratories to determine their quality based on the GIA 4Cs standard: color, clarity, cut and carat weight. Every diamond will have unique qualities: no two will be identical.

A diamond cutter at Diacore Botswana examines the initial facets made on a fancy yellow diamond. Photo: Robert Weldon/GIA

Diamond Treatments

Some manufacturers may try to alter the color or clarity of a diamond to make it more appealing and marketable. The methods used to alter color range from crude ones like coloring girdle facets with a permanent marker, to more sophisticated ones like covering facets with an optical thin film, subjecting the diamond to radiation, or exposing it to high pressure, high temperature annealing. The most common clarity enhancement is fracture filling. All of these may improve the appearance of the diamond, but the seller is legally bound by the FTC to disclose that the diamond has been treated.

$A before and after image of a fractured filled diamond.$

This diamond has been fractured filled to make it more attractive. Photo: Shane F. McClure/GIA.

A 1.05 ct diamond owed its apparent Fancy Light brown-pink color to a coating. After the coating was removed by acid cleaning, the diamond was given a color grade of J

This 1.05 ct diamond owed its apparent Fancy Light brown-pink color (left) to a coating. After the coating was removed by acid cleaning, the diamond was given a color grade of J (right). Photo: Jian Xin (Jae) Liao/GIA

Given their timelessness, resilience and durability, is it any wonder so many choose ”real” diamonds as a symbol of love and commitment? If you’re considering a natural diamond for an engagement ring, be sure to ask for a GIA Diamond Grading Report . The report is your proof that the diamond is natural and that its quality is what the seller describes, giving you the important information you need to make your purchase with confidence. And if you opt for a lab-grown diamond, a GIA Synthetic Diamond Grading Report is your assurance that the material is actually diamond and not an imitation.

Have you ever wondered about do-it-yourself tests to determine whether a specific gem is natural, synthetic or something else? Our post, How to Tell if a Diamond is Real, decodes the most common myths about such tests and why they don’t work.

January Birthstone: What You Need to Know About Garnet

January 3, 2017

Lucky you if yours is the January birthstone. A favorite gem of the Victorian era, garnet comes in a palette of beautiful colors. Read on to gain a deeper appreciation for the gem and the knowledge to shop more wisely.

In this post, we’ll cover:
Types of Garnets
Garnet History & Lore
Where Garnets Come From
Qualities to Look for in a Garnet
Garnet Care & Cleaning

January Birthstone: Types of Garnets

Garnet is a group of minerals that have the same crystal structure but slight differences in chemical composition. Five members of this group are commercially important as gems:

Pyrope (purple to orangy red)
Almandine (purple to orangy red)
Spessartine (oranges and yellows)
Grossularite (colorless to yellow, to reddish orange and orangy red, to vibrant green)
Andradite (yellow and yellowish green)

There are also mixtures of these five species, creating even more colors. Variations in trace elements such as iron, manganese, chromium and vanadium produce the kaleidoscopic color range of garnets.

An array of the many colors of garnet, featuring yellow, orange , deep pink, reddish orange, green, and bluish green.

These are some of the many colors of garnet (top row, from left to right): 16.94 carat (ct) yellow garnet, 19.89 ct orange spessartine, 44.28 ct deep pink rhodolite, 16.99 ct reddish orange garnet, and 7.26 ct green tsavorite. Bottom row, left to right: 8.20 ct greenish yellow garnet, 12.36 ct golden yellow garnet, 9.22 ct pink garnet, 14.53 ct light green grossular, and 4.32 ct bluish green garnet. Photo: Robert Weldon/GIA

Gemologists love garnets for many reasons. For some, it’s the challenge of categorizing new garnet varieties. Others are fascinated by the characteristics of specific varieties. For example, demantoid garnets, the green variety of andradite, may display dramatic horsetail inclusions, which are one of the few internal clarity characteristics that can increase a gem’s value. Gemologists also love demantoid’s dispersion, which is so high that a well-cut gem displays an amazing amount of fire.

Image of horsetail inclusions in a green demantoid.

It’s obvious how horsetail inclusions got their name. Think of them as Mother Nature’s signature in this green demantoid. Photo: John I. Koivula/GIA

This 7.00 ct demantoid from Russia shows why some garnets are so coveted. Photo: Robert Weldon/GIA. Courtesy: Pala International

January Birthstone: Garnet History & Lore

Red garnets have a rich history. Necklaces studded with them adorned the pharaohs of ancient Egypt. Signet rings in ancient Rome featured garnet intaglios that were used to stamp the wax that secured important documents. The clergy and nobility of the Middle Ages had a preference for them.

The Smithsonian’s antique pyrope hair comb is one of the most famous pieces of garnet jewelry (pyrope is from the Greek pyrōpos, which means “fiery-eyed”). A large rose-cut garnet sits at the crest, much like a queen serenely surveying her court. The pyrope garnets that decorate this tiara-like jewel came from the historic mines in Bohemia (now part of the Czech Republic), and these rich red beauties were extremely popular during the Victorian era (1837-1901), when this piece was fashioned.

Antique pyrope hair comb with a crescendo of red garnet.

A crescendo of red, this antique pyrope hair comb would have made a breathtaking statement when worn. Courtesy: Chip Clark, Smithsonian Institution.

Curious about garnet’s reputed health benefits? Red gems like garnet were thought to be remedies for inflammatory diseases, and to soothe the angry heart. Garnet also was thought to cure diseases of the liver.

18K gold Art Nouveau era pin depicts a dragon or gryphon with a red garnet in its mouth.

This fanciful 18K gold pin depicts a dragon or gryphon with a red garnet in its mouth. It was made during the Art Nouveau era (1890-1914). Photo: Eric Welch/GIA. Courtesy: Jana Miyahira-Smith.

January Birthstone: Where Garnets Come From

Russia and Bohemia were important sources of garnet in the 19th century, when they were prized by the Russian royal family and used by the great jeweler Peter Carl Fabergé (1846 – 1920). Tanzania and Namibia are important present-day sources for garnet. The gem is also found in Myanmar, Brazil, Kenya, Iran, Afghanistan, Pakistan, India and Sri Lanka, among other countries.

The rolling hills of Green Dragon mine in Namibia.

Namibia’s rolling hills are the scenic backdrop to the Green Dragon mine – an important modern source for demantoid garnet. Courtesy: Green Dragon Mine

January Birthstone: Qualities to Look for in a Garnet

Here are some helpful tips on selecting a beautiful garnet:

Clarity: Garnet clarity depends on its type. The red garnets almandine, pyrope and rhodolite (a pyrope-almandine) typically do not have eye-visible inclusions. Some of the orange garnets, like spessartine and hessonite (a variety of grossularite), often have eye-visible inclusions. You can use this information to rule out particular gems. For example, you might not want to purchase red garnets that have eye-visible inclusions.
Cut: Many garnets are cut into standard shapes and sizes for easy setting into jewelry. This is especially true of many red garnets. Expensive garnets like fine-quality tsavorite (a variety of grossularite) are cut into shapes and cutting styles that allow more of the weight to be retained from the rough.
Demantoid is often cut to allow the best possible display of its fire. Garnets are also popular for designer cuts and carvings. Red garnets are classic materials for cutting into cabochons and beads. They are commonly found to have high clarity and to be very transparent.
Carat Weight: Garnets can be found in all sizes and weights. Some garnets, like demantoid and tsavorite, are more commonly found as small crystals, so their value goes up significantly with size. Other garnets, like almandine, occur as larger crystals, so there’s no dramatic rise in value as size increases.

Most garnets are more affordable than diamonds, rubies, sapphires and emeralds. This means you should be able to get a larger gem for the same price.

A 6.22 ct spessartine necklace is encircled with 0.40 ct of round diamonds set in platinum and 18K rose gold.

A 6.22 ct spessartine flaunts its beauty in this necklace. Encircling the fiery orange garnet are some 0.40 ct of round diamonds set in platinum and 18K rose gold. Courtesy: Omi Privé

January Birthstone: Garnet Care & Cleaning

The different types of garnet range between 6.5 and 7.5 on the Mohs scale of hardness. This means that garnets are more susceptible to damage than rubies, sapphires and diamonds. So while not all garnets are good candidates far daily wear in a ring, they are ideal for earrings, brooches and pendants.

Give thought to where you store garnet jewelry in your jewelry case. If you let it rub against harder gems–again, think diamonds, rubies and sapphires–it can be scratched.

Garnets might rarely be treated by fracture filling, which is a method of concealing surface-reaching breaks in the gem by filling them with a glass-like substance. Their comparative affordability may be a reason why garnets are infrequently treated. Regardless, warm soapy water is always safe for cleaning garnets. Ultrasonic cleaners are usually safe, except for stones that have fractures or have been fracture-filled. Steam cleaning is not recommended.

A 5.55 ct oval tsavorite garnet ring, with two fancy yellow diamonds weighing a total of 0.71 ct, and 136 round diamonds weighing 1.02 ct total weight, set in platinum.

This award-winning ring by Omi Privé may just take your breath away. It features a 5.55 ct oval tsavorite garnet, two fancy yellow diamonds weighing a total of 0.71 ct, and 136 round diamonds weighing 1.02 ct total weight, set in platinum. Courtesy: Omi Privé

Whether you’re shopping for the January birthstone, or a gem to celebrate your 2^nd wedding anniversary, be sure to download our Garnet Buying Guide. It has the essential tips you need to find the perfect garnet. Take it with you, and shop with confidence.