“Carat” is one of the 4 Cs of diamond quality, measuring the size of loose diamonds by weight. The term comes from the corruption of “carob,” a plant with seeds with nearly uniform mass. Early jewel traders would use carob seeds as counterweights in their scales when measuring gemstones. Modern carat weight is defined as one fifth of a gram.
Instead of carob seeds, today’s jewelers use electronic scales known as micro balances to help grade certified diamonds. These scales have a device in back to alert users if the device is level and able to provide optimal measurements. Micro balances also come with a sealable chamber on which to place the jewel, to reduce outside factors. Once the scale and diamond are ready, the jewel is weighed to the ten thousandth of a carat.
The larger the diamond rough, the rarer. Most gem quality rough loose diamonds are cut down considerably to achieve the desired brilliance and proportions. These factors combine to make larger faceted diamonds unusual and costlier. With all else equal, four quarter carat diamonds will be more affordable than a single one carat diamond.
Natural diamonds don’t form in a vacuum. Their birth environment deep inside the earth exposes the jewels to other elements which mix into the diamond’s crystal. In the vast majority of these cases, this causes diamonds to take on subtle coloring, most often yellow or brown. GIA certified diamonds are graded on a scale of D to Z to determine the degree of these tints.
GIA certified diamonds are evaluated for color with the help of uniform lighting and backgrounds to provide a consistent foundation on which to grade. Master stones representing different ratings are used as points of comparison against the gemstones examined. Along with 23 grades, there are five subcategories of color. D to F is colorless, G to J are near colorless, K to M is faint, N to R is very light, and S to Z is light.
While loose diamonds on the D to Z scale may be referred to as “colorless” or “white” diamonds, this isn’t accurate. Diamonds on the lower end of the scale may appear brown or yellow, and white diamonds are considered a fancy color, or outside the D to Z range. Due to microscopic quirks within their crystal, white diamonds have a hazy, opal like appearance.
Other fancy diamond colors include pink, yellow, green, blue, and other hues in the visible spectrum. Many of these colors, like blue and yellow, come from trace elements mixed within the diamond. Green occurs when natural radiation distorts the diamond’s atomic arrangement, while pink and red are a side effect of defects in the diamond’s lattice structure. Fancy GIA certified diamonds have a unique grading system, with colors graded on a scale determining hue, tone and saturation.
A diamond’s transparency, or clarity, allows light to travel within the crystal, showcasing brilliance and the jewel’s interior. Many diamonds have quirks in their structure, known as clarity characteristics, which may impact its appearance. Clarity characteristics are a byproduct of the jewel’s formation, making flawless certified diamonds extremely rare. Some traits may be subtle, requiring magnification and a trained gemologist to locate, or may be apparent to the naked eye.
GIA certified diamonds are rated along a range of eleven clarity grades, ranging from Flawless to Included 3. Gemstones are examined under 10X magnification, using both a jeweler’s loupe and a microscope. Characteristics are marked on a diagram, noting the location and type of quirks on and within the crystal.
Clarity characteristics in certified diamonds can be divided into two broad categories, blemishes and inclusions. The former occurs on the surface of the stone, such as polish lines and extra facets on the jewel. Inclusions are located inside the diamond, and can range from pinpoint imperfections, healed fractures and even tiny minerals within the diamond crystal.
Grading clarity helps gemologists differentiate natural diamonds from simulants and laboratory made jewels. Clarity characteristics also serve as a diamond’s fingerprints, allowing the gem to be distinguished from others. GIA certified diamonds with Diamond Reports come with clarity diagrams, illustrating the location and nature of inclusions, and letting the owner know how the jewel can be identified.
Cut is a complex member of the 4Cs. It’s often mistaken for the shape, or outline of a diamond. In truth, cut denotes the faceting, polish, proportions and other factors that make a beautiful finished diamond. Ideal certified diamonds cut shows off the best qualities of the jewels, be it brilliance, clarity, color or luster.
What makes a beautiful cut can be subjective. Many types of diamond cut, such as cushion, have no internationally recognized standards for cut. The number and placement of facets, proportions and brilliance can vary greatly while still being attractive. The Gemological Institute of America specializes in grading round brilliant cut loose diamonds, which have strict standards for excellence, making grading more than opinion.
GIA certified diamonds have their cut rated on a five grade range of Excellent, Very Good, Good, Fair and Poor. During grading, jewels are placed on machinery which rotates the stone and makes note of a diamond’s appearance at countless angles. This in turn creates a 3D computer generated model of the stone, enlarged for the gemologist’s benefit and with measurements listed for facets and proportions. From there, gemologists are better able to determine the quality of the diamond’s cut.
For brilliant diamonds, cut is essential to how the stones take in and reflect light. Three types of light are measured, brilliance, fire and scintillation. Brilliance takes in white light and reflects it from the interior of the jewel before exiting the stone. Fire splits white light into the colors of the rainbow and manifests as flashes of color inside the gem. Scintillation is the play of white light and shadows in a jewel. Well cut brilliant certified diamonds will have all three lights balanced within the jewels.
Step cut diamonds downplay the jewel’s brilliance in favor of showcasing the stone’s luster and interior. These stones are often square and rectangular in shape, and may boast cropped corners. Well-made step cut certified diamonds should have concentric sets of parallel facets and even sides.
While brilliant cut diamonds are beloved for their sparkle, they sacrifice large amounts of carat weight to shine their best. Step cut diamonds have less shimmer, but preserve more carat. Mixed cut diamonds were developed to promote brilliance while keeping more of the loose diamonds’ rough. This usually manifests as a step cut lower half and a brilliant upper.
It can be difficult to determine what makes a quality diamond cut. Not only is there a variety of styles such as brilliant, step and mixed, within each category are different types of loose diamonds with a range of standards as to what makes them beautiful. This can make certifying a diamond’s cut a complicated process.
The round brilliant cut alone has several different guidelines on how to achieve peak brilliance in loose diamonds. All are variations of a cut developed in 1919 by the diamond specialist Marcel Tolkowsky. His original design specified the number and types of facets, and proportions needed to reflect great amounts of light through the diamond and back to the viewers’ eyes. Later standards have sought to improve upon the original model, such as by faceting the initially knife edge girdle, and by enacting stricter ideals for height and depth ratios.
Other round brilliant variations run in the opposite direction. Some versions may add a greater quantity of facets to loose diamonds, such as 81 instead of the traditional 57. As with round brilliants that adhere closer to Tolkowsky’s vision, the goal behind the less conventional designs is to enhance the light return of a diamond.
Examples of differing cut standards include step cut diamonds like the Asscher. It was initially developed in 1902 by the Royal Asscher Company as a square diamond with cropped corners and 58 facets. A similar cut, the Royal Asscher, was created in 1999 with an additional 16 facets and increased brilliance. The individual cuts can vary by proportion and angle. Princess cut diamonds are similar, with their facets and number of chevrons changing by what the cutter thinks produces attractive loose diamonds.
Independent laboratories such as the Gemological Institute of America aim to provide easily understood, unbiased grades for certified diamonds. With cut, evaluation can be complicated due to the many ways diamonds can be faceted. Diamonds with stricter standards such as the round brilliant are easier to rate, while other cuts such as the Asscher provide more of a challenge.
Why Certified Diamonds?
The diamonds used at Valentin Magro are certified by the Gemological Institute of America. Each of these gemstones come with a report detailing the qualities of its jewel. GIA certified diamonds also come with unique identification numbers, making verification easier as well as distinguishing individual diamonds from one another.
To ensure our clients receive reliable information regarding their certified diamonds, we use an independent third party laboratory. This step ensures that there’s as little bias as possible with the diamond grading. We want the best for your clients, which includes honesty.
We make jewelry with GIA certified diamonds for several reasons. The first is that GIA has a long history of research and innovation. Their laboratories have advanced equipment and software for diamond grading. GIA also improves upon its grading procedures, modifying their approach when necessary, such as introducing laser inscriptions to provide easier identification.
Among GIA’s innovations is the creation of the 4Cs of color, cut, clarity and carat as an impartial measure by which to determine a diamond’s quality. Within each C is a rating scale to determine the level of quality in the stone. All of this is outlined in simple terms so that gemologists and lay people alike can understand the grades. One of the reasons we use GIA is so that you too can have a clear idea of your certified diamonds’ attributes.