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The Four Cs of Diamonds

0.25 Carat

4.1 mm

0.50 Carat

5.0 mm

0.75 Carat

5.8 mm

1.00 Carat

6.5 mm

1.50 Carat

7.4 mm

2.00 Carat

8.2 mm

The Carat Weight

The word carat derives from the word carob, a Mediterranean seed, which has an extremely consistent weight for measuring. The greater the carat weight, the rarer, and more valuable the diamond becomes. Five metric carats weighs exactly 1 gram.

Some people want the largest diamond possible. If size is a priority, we at Geoffreys Diamonds & Goldsmith can help you classify the proper cut, color and clarity to fit your budget economically, and fit your jewelry beautifully. Many of our engagement rings can fit diamonds up to 5.00 carats, but each ring has different size constraints based on its size and the type of setting. Prong settings can be manipulated to fit virtually any size diamond, but tension-set diamonds and bezel set diamonds have more limitations on size.

Too Shallow

Ideal Cut

Too Deep

The Cut

Diamonds are renowned for their ability to transmit light and sparkle intensely. We often think of a diamond's cut as shape (round, emerald, pear), but a diamond's cut grade is really about how well a diamond's facets interact with light.

Precise artistry and workmanship are required to fashion a stone so its proportions, symmetry, and polish deliver the magnificent return of light only possible in a diamond. A diamond's cut is crucial to the stone's final beauty and value. And of all the diamond 4Cs, it is the most complex and technically difficult to analyze.

To determine the cut grade of the standard round brilliant diamond - the shape that dominates the majority of diamond jewelry – GIA calculates the proportions of those facets that influence the diamond's face-up appearance. These proportions allow GIA to evaluate how successfully a diamond interacts with light to create desirable visual effects such as:

Brightness: Internal and external white light reflected from a diamond

Fire: The scattering of white light into all the colors of the rainbow

Scintillation: The amount of sparkle a diamond produces, and the pattern of light and dark areas caused by reflections within the diamond

GIA's diamond cut grade also takes into account the design and craftsmanship of the diamond, including its weight relative to its diameter, its girdle thickness (which affects its durability), the symmetry of its facet arrangement, and the quality of polish on those facets.

The GIA diamond cut scale for standard round brilliant diamonds in the D-to-Z diamond color range contains 5 grades ranging from Excellent to Poor.

The true definition of cut is the quality of the proportions and symmetry of the diamond. Your diamond's proportions make a vast difference on how brightly your diamond shines. An 'ideal cut' diamond is one that allows the maximum amount of light to return through the top of the diamond, which takes into consideration the depth, table size, crown height and angle, girdle thickness and more. Our diamond professionals will be happy to assist you in selecting the best diamond cut.


Rough diamonds generally do not show their beauty, they must be cut and smoothed to exhibit the desired brilliance. Diamonds are generally cut into a variety of shapes, each having unique characteristics.


The "brilliant" cut diamond is also the most popular on the market today. A diamonds "cut" has many facets which determine the overall brilliance. More than 100 years ago, a Russian Mathematician named Marcel Tolkowsky calculated the number of cuts necessary to create the reflective properties desired, the fire of a diamond. Today, many advanced scientific methods are used by the GIA and high end designers to create truly brilliant diamonds, the industry standard for round diamonds being 57 facets. This means a round brilliant cut has 57 incredibly small faces all around the top, creating an ideal amount of ways for light to expose the inherent beauty of the diamond.


This cut today is considered a classic style, being more common in the past because of it's larger rectangular facets being less intricate. A truly brilliant emerald is a stunning example of elegance even now. The larger more open faces allow for more light to refract from one angle, usually creating a brighter shine or sparkle. Even with modern science there is no way to ensure a perfect cut. Jewelers through years of experience will be able to inspect many of these criteria with a high degree of precision, yet we are still having a hard time measuring such features at the precision required for modern science. If the diamond is cut too deep, light will escape through the sides making the gem appear darker than desired. If the diamond is cut too shallow, light will be lost out of the bottom losing brilliance.


Inspired by a round cut, the radiant cut shares many features including fire and brilliance. The shape of the gem itself is closer to an emerald, being square but lacking the stair case steps of the emerald instead featuring facets closer to that of a round cut. The overall feel of the cut is closer to that of an emerald because of its closer to square shape. Despite this difference, the radiant cut gives off much more fire than an emerald because of its facets.


A square from the top, the princess cut signifies absolute brilliance and is the second most popular cut in the world. Known for its sharp uncut pointed corners and collection of 58 facets, it offers a fire and brilliance unparalled. Originally it was known as the Barion cut devised in the 1960's by Basil Watermeyer and named using his 1st initial and all but the 1st letter of his wife's name, Marion. Some say it was considered a "crown" by Basil to his wife. Today it has gained prominence as a distinctive symbol of elegance with its high degree of light return relative to a round cut but having a squarish shape closer to an emerald.


Almost 100 years old, this cut has gained prominance in recent times because of its signature octagon shape, with the inclusion of stair steps from an emerald cut. Also known as the modified square emerald cut, it features a higher crown (taller) with a smaller top face allowing for 72 wide step facets that create a shine rivaling that of the round brilliant cut. The relatively round shape draws the eye towards the center of the diamond and the wider facets.


This cut is commonly termed an ovular shape. It came into commonality relatively recently yet it has a classic romance feel that sets it apart from the rest. It contains some of the largest side facets of any other cut, creating an overall brilliance that's incredibly powerful.


This cut is an ovular take on the round brilliant cut. Featuring many of the same features including brilliance and fire, the oval accents slender profiles and skinny fingers. It's a great alternative to the most popular cut, the round.


This cuts brilliance and fire is only beaten by it's one of a kind symbolism. The absolute representation of love with the same brilliance of the round cut. It's actually a wide pear shape with a dip inwards at the top to create the shape that is truly breathtaking.


Also known as a teardrop, this cut used to be the most popular in the world during the renaissance period but then fell out of the spotlight. Ideally it has 58 facets with a wide variation on the shape of the facets because of the uneven outline of the gem. This creates a varying degree of brilliance that captivates many.


Sometimes referred to as the Navette Cut, this lesser common shape has a rich background. Known for its smile shape, it was made for Louis XIV after he wanted a diamond shaped like the smile of his mistress, Marquise de Pompadour.







The Color

The diamond color evaluation of most gem-quality diamonds is based on the absence of color. A chemically pure and structurally perfect diamond has no hue, like a drop of pure water, and consequently, a higher value. GIA's D-to-Z diamond color-grading system measures the degree of colorlessness by comparing a stone under controlled lighting and precise viewing conditions to master stones of established color value.

GIA’s diamond D-to-Z color- grading scales is the industry's most widely accepted grading system. The scale begins with the letter D, representing colorless, and continues, with increasing presence of color, to the letter Z. Many of these color distinctions are so subtle that they are invisible to the untrained eye; however, these distinctions make a very big difference in diamond quality and price.

D - Colorless
E-F - Colorless
G-J - Near Colorless
K-M - Faint Yellow
N-R - Very Light Yellow
S-Z - Light Yellow

Why does the GIA color grading system start at D? Before GIA universalized the D-to-Z color grading scale, a variety of other systems were used loosely, from A,B, and C (used without clear definition), to Arabic (o,1,2,3) and Roman (I,II, III) numbers, to descriptive terms like “gem blue” or “blue white,” which are notorious for misinterpretation. So the creators of the GIA Color Scale wanted to start fresh, without any association with earlier systems. Thus the GIA scale starts at the letter D. Very few people still cling to other grading systems, and no other system has the clarity and universal acceptance of the GIA scale.

Are Zs considered fancy-color? No. Naturally colored diamonds outside the normal color range are called fancy-color diamonds. The FTC provides no guidelines for the use of the term “fancy-color” in the US, but there are general agreement in the international trade that fancy-color diamonds are either yellow or brown diamonds that have more color that a Z masterstone or they exhibit a color other than yellow or brown.

Unlike colorless and near-colorless diamonds, fancy-color diamonds are evaluated less for brilliance or fire and more for color intensity. Shades that are deep and distinct are rated higher than weak or pale shades.

GIA describes color in terms of hue, tone and saturation. Hue refers to the diamond's characteristic color, tone refers to the color's relative lightness or darkness and saturation refers the color's depth or strength. Using highly controlled viewing conditions and color comparators, a fancy color grader selects one of 27 hues, then describes tone and saturation with terms such as "Fancy Light," "Fancy Intense," and "Fancy Vivid." The color system GIA developed is used worldwide.







The Clarity

Diamonds are composed of mostly carbon. During the heating process, other elements become trapped inside, giving each diamond its own unique fingerprint. These inclusions help identify the clarity of your diamond.

F - No inclusions or blemishes are visible to a skilled grader.
IF - No inclusions and only blemishes are visible to a skilled grader.
VVS1-VVS2 - Inclusions are difficult for a skilled grader to see.
VS1-VS2 - Inclusions are clearly visible but can be characterized as minor.
SI1-SI2 - Inclusions are noticeable to a skilled grader.
I1-I3 - Inclusions are obvious and may affect transparency and brilliance.

*All diamonds are viewed through a 10x magnification lens by diamond graders.