Buying Guide to Diamond Jewelry

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Diamonds are uniquely rare and hard to find. They are also strong, enduring and beautiful —the same characteristics that define true love. A coincidence? We think not. What are you looking for in the perfect diamond? This guide will help understand the basics you should know before purchasing your diamond.

Jewelry: Diamond

What do you really need to know in selecting a diamond?

The first step to choosing the right diamond is learning the 4 C's: Color, Cut, Clarity and Carat.

The GIA set the standard for a diamond’s quality with the International Diamond Grading System. Created by this non-profit organization the Gemological Institute of America’s (GIA) in the middle of the 20th century, the 4 Cs of diamond evaluation became the accepted standard world-wide. The institution of these guidelines means that diamonds are evaluated on a universal, global basis and will present close quality grades (the 4 Cs) in any country.

Aren't diamonds colorless?

Yes and no. The color of a diamond is actually graded before it is set into jewelry and influenced by the surrounding metal color. Diamonds are prized for their absence of color, with the highest value awarded to chemically pure and structurally perfect stones.

Colorless, clear diamonds, sometimes called white diamonds, are the basis against which all other diamonds are graded. Using a lettering system from D-Z, only the most rare, colorless, diamonds receive the coveted “D” rating. “Colorless” diamonds are rated D-E-F; nearly colorless: G-H-I-J; faintly tinted: K-L-M; lightly tinted, with a slight yellow cast apparent to the naked eye: N-O-P-Q-R; visible yellow tint: S-T-U-V-W-X-Y-Z. The examples below will give you a good idea of the color range diamonds come in. Often times, these color distinctions are so subtle; they are invisible to the untrained eye. Note: yellow, brown or colored, “Fancy” diamonds, however, are not subjected to the D-Z grading scale. These fancy-colored diamonds are considered outside of the normal color range.

Colorless Diamonds





Is the cut of the diamond the same thing as the shape?

Cut and shape are very different things. Shape refers to the diamond’s style (e.g. round, oval, and pear). A diamond’s cut is the single most important characteristic of the stone, and usually what is referred to as its “sparkle” or reflective qualities. A good cut gives the diamond its “brilliance.” Cuts should be precise and well defined to give the diamond its beauty. It is the angles and finish that determine how the diamond will reflect light. A well-cut diamond will reflect more light back out through the top or “crown” of the stone than through its bottom or sides. The “cut grade” is defined as the measure of the gem’s “light performance.” The GIA’s Cut Scale ranges from Excellent to Poor.

Cut Scale Grading Chart:

Excellent Reflecting maximum fire and brilliance; creating exceptional sparkle.
Very Good Appears similar to Excellent grade under normal lighting conditions demonstrating superior fire and brilliance.
Good Reflects a majority of light that enters the diamond for above average appearance.
Fair Fair ratings are acceptable in diamonds of less than .75 carats where it is difficult to perceive differences in sparkle.
Poor Diamond cuts appear noticeably dull and lifeless even to the naked eye. Fair and poor graded diamonds are generally cut to maximize carat weight of the diamond.

What is the significance of single cut versus full cut diamonds?

In looking at diamond cuts, and evaluating brilliance, know that there are full cut diamonds and single cut diamonds. The actual cutting or fixing the arrangement of facets (angles), helps determine whether the diamond is full cut or single cut. A full cut round diamond is a diamond that has 57 or 58 facets and is also known as a round brilliant cut. Comparing the modern round brilliant cut to “fancy cuts” (e.g., emerald cut, pear cut, etc), various quantities of facets would commonly exist, however, the round cut at 58 facets is still considered a classic shape for diamonds. Round diamonds having less facets are not considered full cut diamonds. Round diamonds that have 17 to 18 facets are considered single cuts and do not possess the brilliance of a full cut diamond. Single cut diamonds are used primarily as secondary diamonds in a piece of fashion diamond jewelry, or where the more expensive full cut diamonds are not necessary or warranted.

Professionals’ use three more terms when rating a diamond’s cut.

The gemologists consider 3 things when rating the cut of a diamond: brightness, fire and scintillation.
Brightness is defined as: the internal and external white light reflected from the stone.
Fire means: how the light “scatters” using all the colors of the rainbow.
Scintillation is described as: the amount of sparkle a diamond creates and the pattern of light and dark areas caused by reflections within the gem.

What should you know about the next "C" clarity?

The clarity of a diamond is the assessment of the number of “birth marks,” usually called inclusions, within the stone. Since the inclusions affect the way the light passes through the diamond (and therefore, its sparkle), the fewer the inclusions, the better clarity and more expensive the diamond. These inclusions are also natural and define that 2 two diamonds are exactly a like. This clarity factor of judging a diamond is accomplished through the determination of how many, how big, and how light passing through the stone is negatively affected by these inclusions, as well as where within the diamond these inclusions are situated. These inclusions exist within a stone because small crystals and imperfections were trapped inside the diamond during its creation. Diamonds that are sold with certification will usually contain a diamond map showing the stone’s inclusions. The GIA provides 11 grades for clarity.

Clarity Scale Grading Chart

FL = Flawless No inclusions under 10x binocular magnification.
IF = Internally Flawless No inclusions, only slight surface blemishes.
VVS1 – VVS2 = Very Very Slightly Included Tiny inclusions that are difficult for a skilled grader to see under 10x magnifications.
VS1 – VS2 = Very Slightly Included Minor inclusions including small crystals, feathers, distinct clouds or groups of pinpoints.
SI1 – SI2 = Slightly Included Noticeable inclusions seen easily under 10x magnification, such as crystals, clouding, feathers.
I1, I2, I3 = Imperfect Obvious inclusions easily seen with the naked eye. These inclusions may threaten durability.

To help you visualize these ratings take a look at this illustration.

Diamond Clarity

You should know that diamonds are sized by their weight.

The fourth C is the term carat, which refers to the weight of the diamond. One carat is made up of 100 points. So a diamond that is 50 points in weight is referred to as .50 (half) a carat. Weights that exceed one carat are expressed in carats and decimals. For example, a 1.05 diamond would be described as "1.05 carats."

Diamond Carat Weight

0.50 ct.

0.75 ct.

1.00 ct.

2.00 ct.

5.00 ct.

Usually, but not always, the larger the carat size, the more costly the gem. However, this is not always the case. The other 3 Cs will play a large part in determining the value of the stone as well, and a smaller stone with better cut, clarity and color can have a higher value.

Carat Points Diameter (approx.)
.25 25 4.1mm .25 Carats
.5 50 5.2mm .5 Carats
.75 75 5.7mm .75 Carats
1 100 6.5mm 1 Carat

How do diamonds shape up?

Once you have an understanding of the 4 Cs, think about what shape you prefer. Shape is a personal preference. There are multiple shapes available with the most common illustrated below. Remember that the diamond cutter will determine the shape of the diamond by (1) maximizing the stones weight and (2) and by balancing the application of facets being applied to the stone during cutting with where the inclusions and imperfections will be least likely to affect the light passing through the stone.

Diamond Shapes

What Are Color-Treated Diamonds?

Very different from the D-Z method of classifying a diamond’s natural color, a color-treated diamond is a diamond that has been put through a man-made treatment process to either remove or refine color, or to add a "fancy" color (blue, green, orange, pink, etc…). Natural "fancy" colored diamonds are very rare and expensive; a color-treated "fancy" diamond is much less expensive.

Color Treatment Effects & Advantages Disadvantages
Irradiation Color Treatment The color of a diamond can be altered artificially in a controlled environment through the bombardment of high-energy particles, such as gamma rays, electrons, protons, neutrons, and others. This process creates a physical change of the diamond at the atomic level, which in turn causes light to refract (bend) through the diamond in a different way, causing a bluish-green color to form. Irradiated diamonds are then typically "finished" in a heating process known as annealing, which allows further control of the color, and many more available hues. A big advantage to irradiation is that it allows for creation of so-called "fancy" diamond colors (intense blues, greens, oranges, pinks, etc…) at a low price; naturally-occurring "fancy" colored diamonds are incredibly rare and priced accordingly. A side benefit of irradiation is its ability to help cover imperfections in the diamond. While the coloring of an irradiated diamond is permanent, it is possible for the color to be altered further if the diamond was exposed to high heat in the future. For most purposes, however, the coloring will not fade or change over time.

What is the difference between lab created diamonds, synthetic diamonds, and simulated diamonds?

Synthetic diamonds (also known as cultured or cultivated diamonds) are diamonds produced in an artificial process, as opposed to natural diamonds, which are created by geological processes. While consumers associate the term synthetic with imitation products, lab created diamonds are actually made of the same material as natural diamonds (pure carbon, crystallized in isotropic 3D form). In the U.S., the Federal Trade Commission has indicated that the alternative terms laboratory-grown and laboratory-created, would more clearly communicate the nature of the stone.

A diamond simulant, diamond imitation or imitation diamond is an object or material with gemological characteristics similar to those of a diamond. Simulants are distinct from synthetic diamond, which is an actual diamond having the same material properties as natural diamond. Enhanced diamonds are also excluded from this definition. While their material properties depart markedly from those of diamond, simulants have certain desired characteristics – such as dispersion and hardness – which lend themselves to imitation. Trained gemologists with appropriate equipment are able to distinguish natural and synthetic diamonds from all diamond simulants, primarily by visual inspection. The most common diamond simulants are high-leaded glass (e.g., rhinestones) and cubic zirconia (CZ), both artificial materials.

Although diamonds are one of the hardest materials on Earth, they are not indestructible and should be treated with care.

They can scratch or chip when in contact with other diamonds and should be separated when stored, perhaps in a padded box or pouch.

In addition, the diamond's setting may also become loose through normal wear over time. To prevent losing a precious stone because it fell out of a loose setting, bring your diamonds to a jeweler for periodic check-ups, tightening the prongs, or getting the prongs re-tipped.. While you’re there, have the jeweler professionally clean your diamonds to keep them sparkling their brightest.

In between professional cleanings, however, shine your diamonds with a soft tooth brush and warm, mild, soapy water. Commercial cleansing solutions are also available and can be used with great results by following the directions provided.