- HOME
- >
- CONSUMER RESOURCES
- >
- HOW TO BUY A DIAMOND
How to Buy a Diamond
In ancient Greece and Rome, diamonds were supposedly thought to be tears of the gods or splinters of fallen stars. Through the centuries, their symbolism has become both infinitely grand and intimately personal. Today, they are icons of purity, strength, bravery, eternal love, and, in the unforgettable opinion of Marilyn Monroe, ultimate friendship.
Natural Diamonds
Natural diamonds are created about 100 miles below the earth’s surface. There, in molten rock, intense heat and pressure initiate a reaction that transforms carbon. Each carbon atom bonds to four others, and builds the strong crystalline structure of the gems.
Diamonds are brought to the surface by powerful volcanic eruptions. They travel in magma, via channels called kimberlite pipes (named for the Kimberly, South Africa location where they were first found). When the magma cools, it becomes kimberlite rock — yellow or blue matter that includes the diamonds. Over time, geological activity, particularly of water and glaciers, can move the diamonds to secondary locations, such as riverbeds. Depending on the site, stones are retrieved by machine or by hand, and then, typically, cut and polished.
Historically speaking, most natural gemstone-grade rough diamonds have come from Africa. Today, important sources also include Canada, Russia, and Australia. But, these stones can be found nearly anywhere in the world, except Antarctica.
Lab-Grown Diamonds
Lab-grown (also known as synthetic) diamonds are man-made stones, typically created through high pressure and high temperature (HPHT) or chemical vapor deposition (CVD). Both methods create stones with essentially the same chemical, physical, and optical properties as natural diamonds.
Diamonds
Diamonds that are colorless or near colorless are known simply as diamonds, or white diamonds. These traditional-looking stones are legendary for their brilliance and capacity to reflect light. They can be created by nature or by man. Yet, nature’s version is, by far, more valuable.
Colored Diamonds
Diamonds distinguished by hue, tone, and saturation are called colored diamonds. These stones come in a rainbow-like range of yellow, pink, blue, green, etc. Natural colored diamonds get their singular shades from elements (such as nitrogen, hydrogen, or boron) or unusual environmental or developmental factors (such as radiation). These colors can get an extra boost from some sophisticated treatments. In fact, colored diamonds can be entirely lab-grown. But, the most prized of these diamonds come by their color naturally.
Diamonds can be the focal point of an endless range of stunning necklaces, bracelets, pendants, rings, earrings, and brooches. Diamonds are typically placed in gold or platinum, in a variation of one of these popular settings:
Bezel
Channel
Halo
Invisible
Pavé
Prong
Solitaire
Tension
Three Stone
a diamond encircled by a rim, usually near its girdle
diamonds set side-by-side, flush between two vertical strips
a ring of diamonds, surrounding a larger center diamond
diamonds placed closely, usually in a row, held by a concealed setting
many small diamonds set closely in a frame, to create an encrusted effect
a diamond held by “claws” (usually 4–6), which bend at the stone’s crown
a single stone, typically mounted with prongs
a diamond suspended between two sides of a band, so it appears to float
three stones mounted in a row, each in its own prong setting
Each diamond is completely unique. Its individual charm will depend, in large part, on the classic “Four Cs”: carat, clarity, color, and cut. But, an expert eye can reveal deeper secrets. A gemological report from a respected, independent laboratory, like EGL USA, can note a stone’s natural versus lab-grown foundation, treatments applied to enhance its appearance, environmental friendliness, and true light performance.
While the final selection is purely personal, many of these aspects — even those that are subtle — can make a big difference in determining a stone’s visual appeal and value.
Important quality-related diamond terms include:
Carat Weight
Diamonds are measured by weight. One carat (ct.) equals 1/5 of a gram. All other qualities being equal, larger natural diamonds tend to be more costly, due to their scarcity. However, carat weight is entirely a matter of taste. And the perceived size of a diamond will depend not only on its weight, but also on factors such as its cut or setting.
| Carat | 0.10 | 0.25 | 0.50 | 1.00 | 1.25 | 1.50 | 1.75 | 2.00 | 2.50 | 3.00 |
| Diameter (mm) | 3.0 | 4.1 | 5.2 | 6.5 | 6.9 | 7.4 | 7.8 | 8.2 | 8.8 | 9.4 |
| Height (mm) | 1.8 | 2.5 | 3.1 | 3.9 | 4.3 | 4.5 | 4.7 | 4.9 | 5.3 | 5.6 |
Clarity Grade
The process that creates a diamond can also create its unique internal or external characteristics. These characteristics vary in shape, size, position, etc.; and they (as well as any applied treatments) can impact the stone’s appearance. On a gemological report, these details may be shown on a plotting diagram.
Taken together, the characteristics result in a clarity grade ranging from FL (flawless) to
I (included), divided into 12 sub-grades, as shown below. Other quality factors being equal, flawless clarity is exceptionally rare and valuable. However, to the naked eye, stones with less perfect grades can also be beautiful.
(Flawless) describes diamonds in which a skilled observer does not see any inclusions or surface blemishes, after thorough examination at 10-power magnification under standardized lighting conditions.
(Internally Flawless) describes diamonds that have no internal characteristics observable under the conditions described above, but that may have minor blemishes confined to the surface.
(Very Very Slightly Included) describe diamonds with very, very small inclusions that are difficult for a skilled observer to see, under the conditions described above.
(Very Slightly Included) describe diamonds with very small inclusions ranging from difficult to somewhat easy to observe, under the conditions described above.
(Slightly Included) describe diamonds with small inclusions that are easy or very easy to see, under the conditions described above. Occasionally, inclusions in the SI category are visible to the unaided eye.
(Included) describe diamonds with medium or large inclusions that are usually obvious to the unaided eye, under standardized lighting conditions.
Note: All of the grades above assume skilled observation at standardized lighting conditions.
Color Grade
A classic diamond, typically, has little or no color at all. Colorless to light diamonds are graded on a scale from “D” (colorless) to “Z” (possessing a strong tonal modifier, which is typically yellow, but can be brown, gray, green, pink, etc.) Due to their scarcity, natural colorless diamonds tend toward high prices.
Colored diamonds can also be spectacular. The boldest of these are called fancy colored diamonds, and they are graded on a scale from fancy light to fancy vivid. While remarkable diamonds exist in many colors (from varied sources), natural fancy vivids are typically the most rare and valuable.
The examples below depict these variations for a yellow diamond.
Cut (Shape and Style)
Cut describes the silhouette of a diamond — a combination of shape and, often, style, as shown below. Lovely stones can be found in virtually any shape or style.
Sample Shapes
HEART
OVAL
PEAR
PRINCESS
ROUND
Sample Styles
Top (Crown) View Side (Pavilion) View
BRILLIANT
STEP
MIXED
Cut Grade
The cutting and finishing of a diamond requires precise attention to detail. Cut grade ranks the combined impact of several key factors of this work: a diamond’s proportions, polish (surface quality), and symmetry (contour/outline exactness). On an EGL USA report, the most exceptional cut grade is “ideal plus”.
Light Performance
A diamond’s magic comes largely from its interaction with light. This “light performance” is
a combined effect: the way a diamond returns light, plus its brightness and sparkle or “life.”
All of these aspects can be scientifically measured; and superior performance in any one of them can yield a beautiful stone. Upon request, EGL USA can take this analysis a step further, combining it with nine other traditional measurements, to determine a stone’s overall visual appeal: the Diamond’s Natural Attraction (DNA)™.
Note: All photos and diagrams above are intended as general guides.
Renderings may vary with computer settings.
The most famous diamonds in the world are known for their combination of exceptional beauty, size, quality, and, even, mythology.
The 3,106-carat Cullinan is the largest diamond crystal every discovered. The Cullinan was found in South Africa in 1905, and was later cut into nine large and 96 small stones. One of these — the Great Star of Africa (or Cullinan I) — is the largest flawless cut diamond in the world. A tremendous 530.20 carats, this pear-shaped stone is set in England’s Sovereign’s Sceptre.
The 317.4-carat Second Star of Africa (Cullinan II) also comes from the Cullinan.
This cushion-cut stone adorns the Imperial State Crown.
The Koh-i-Noor (Mountain of Light) is a 105.6-carat oval brilliant stone that came to England as a controversial spoil of war from India. The diamond, which is set in the crown of Queen Elizabeth the Queen Mother, supposedly brings bad luck to men.
The Koh-i-Noor, Great Star of Africa, and Second Star of Africa are all secured in the Tower of London, with the other Crown Jewels.
The cushion-shaped, 140.64 carat Regent Diamond was discovered in India in 1696 and later owned by a succession of French royals. Most famously, the stone may have decorated the hat of Marie Antoinette, as well as the sword of Napoleon Bonaparte. The Regent is displayed at Paris’ Louvre Museum, along with other notable diamonds: the pale yellow Sancy and pale pink/orange Hortensia.
The blue Hope Diamond is a gorgeous 45.52-carat natural fancy deep grayish-blue stone.
It is thought to have been found in India in the 1660s. Through history, this cushion antique brilliant cut stunner was considered cursed, leading to the demise of its many owners.
It is safely displayed at the Smithsonian in Washington, DC.
The signature sparkle of any diamond can be maintained with careful cleaning. For natural diamonds only, soak for a few minutes or use a soft cloth to apply an alcohol-based cleaning solution. Then, brush gently with a very soft, clean toothbrush. For all other diamonds, use a mild liquid detergent and water. Be sure to clean the front and back of the diamond. Then, rinse it with water and dry it with a lint-free cloth.
Never use any chemical or abrasive cleaners on a stone or its setting. If the jewelry is set in rhodium, do not use ammonia. If the jewelry contains any other types of gemstones, use the best cleaning method for the least durable stone.
Diamonds should be stored separately, in a soft pouch. And mountings should be checked regularly by a professional jeweler. A jeweler should also be consulted if additional cleaning of the stone is needed.
For more information on EGL USA Diamond Reports, contact EGL USA customer service at 888 EGL USA4 (888 345 8724) or info@eglusa.com.