A diamond’s color grade actually refers to the absence of color. In other words, diamonds that are white, containing little or no color, receive higher quality grades than those with noticeable color.
A chemically pure and structurally perfect diamond has no hue, like a drop of pure water, and consequently, a higher value.
A color scale established by the Gemological Institute of America (GIA) assigns a letter to the degree of colorlessness found in a diamond. Beginning with D and ending with Z, each descending letter denotes an increasing amount of light yellow, brown or gray in the diamonds.
Color of the polished diamonds starts from Colorless D-F), near colorless (G-J), faint color (K-M), very light color (N-R), light color (S-Z) to fancy color (Z+). In diamond trade terminology is referred in alphabet starts from D to Z.
Diamond carat weight is the measurement of how much a diamond weighs. A metric “carat” is defined as 200 milligrams. Each carat can be subdivided into 100 ‘points.’ This allows very precise measurements to the hundredth decimal place.
Carat reflects the weight of the stone, which includes depth, height and diameter of the stones. Prior to the twentieth century, diamonds were measured using carob seeds, which were small and uniform and served as a perfect counter weight to the diamond. The word “carob” is the origin of the word “carat” that we use today.
One carat is the equivalent of 0.2 grams One carat is also divided into 100 points. Points are generally used to describe increments of weight within a carat. The weight of a 3/4-carat diamond can be shown as .75 carats or 75 points.
A diamond’s CUT not only refers to its shape, but also how effectively the stone can return light back to the viewer’s eye. A well-cut diamond will appear very brilliant and fiery, while a poorly cut stone can appear dark and lifeless. CUT verification can be done through comparison of parameters of facets. A well cut diamond will be symmetrically round, proper depth and width, and have uniformity of the facets.
A diamond cutter will follow precise mathematical proportions relating to the height, width and depth of the crown (top), girdle (widest part) and pavilion (bottom). When a diamond is cut to the right proportions, light reflects from one facet to another and then disperses through the top of the stone, resulting in a burst of fire and brilliance. Fire is the flashes of color one sees when you look at a diamond; brilliance is its sparkle.
Polish is the overall condition of the surfaces of a finished diamond. Polish is rated Good (GD), Very Good (VG), Excellent (EX), and Ideal (ID).
Symmetry refers to the precision of the shape and arrangement of facets in a diamond. Although to the naked eye finish features only have a tiny effect on appearance, symmetry is an significant aspect.
Clarity is basically inclusions in diamonds. Clarity can be categorized as following, Flawless (FL), internal flawless (IF), very very slight inclusions (VVS), very slight inclusions (VS) , slight inclusions (SI) and lowest clarity scale id Inclusion (I).
It is near to impossible to have a diamond without impurities. Diamonds without inclusions or blemishes are rare. Often invisible to the naked eye, these natural blemishes are categorized as – inclusions, which are internal, and blemishes, which are external. When the stone was being formed sometimes trace elements or minerals get trapped that result in inclusions that appear as feathers, clouds or crystals. Scratches and chips visible to the naked eye are known as blemishes.
FL, IF:Flawless, Internally Flawless. There are no inclusions – internal flaws – or blemishes – external flaws.
VVS1, VVS2: Very, Very Slight Inclusions. Hard to view such inclusions under 10x magnification. An excellent quality diamond.
SI1, SI2: Slight Inclusions. Inclusions are visible under 10x magnification and may not be visible to the naked eye when the stone is in the face-up position.
I1, I2, I3: Included: Inclusions are obvious under 10x magnification and may affect transparency and brilliance. I1 diamonds have inclusions that are almost always visible to the naked eye.
Eye Clean Diamonds
What Are Eye Clean Diamonds?
Universal Jewels & Diamonds considers a diamond eye clean if the diamond appears to be free of inclusions when viewed face up in daylight (or fluorescent lighting) by the naked eye (with 20/20 vision) from a relatively short distance (6-12 inches).
The concept of an eye clean diamond varies slightly in definition from retailer to retailer, but three major factors influence the definition of eye clean diamonds:
1) Distance and point of reference
2) The lighting under which the diamond is evaluated
3) The vision of the viewer
According to GIA and AGS, diamonds that are considered Flawless (FL), Internally Flawless (IF), Very, Very Slightly Included (VVS1 and VVS2) and Very Slightly Included (VS1 and VS2) are considered eye clean.
On the other hand, Slightly Included (SI1 and SI2) diamonds may or may not be eye clean. They need to be assessed individually to see if they are a good value.
Included (I1, I2 and I3) diamonds are considered non eye clean.
Ideal Cut Diamonds
An ideal cut diamond is a round, brilliant, or princess cut diamond that is cut to ideal proportions and angles and has excellent polish and symmetry ratings. An ideal cut diamond reflects almost all the light that enters it, and is among the rarest cuts. The ideal cut diamond is used as benchmark for grading all other diamonds. In America, ideal cut proportions are often determined by the American Gem Society Laboratory (AGSL), but different countries and different companies base their idea of the ideal cut on different standards.
Back in the 1900s, Belgian diamond cutter, Marcel Tolkowsky, coined the term- Ideal Cut. After analyzing the round brilliant cut diamond, he took both brilliance (the amount of the white light reflected) and fire (the separation of white light into its spectral colors) into consideration. While his calculations serve as a guide for today’s idea of the global “ideal cut” standards, countries have still made their own modifications.
Tolkowsky’s ideal cut is not perfect, but it nevertheless serves as a basic guideline for ideal cut diamonds. Today, we also use the guidelines of a gemstone cutter named Bruce Harding who developed another model in the 1970s as well as other computer models and technological scopes.
Ideal diamonds are perfectly proportioned to refract light, producing that fire and brilliance up through to the table and crown. There are at least six “ideal cuts” being used today but only three of them (including the one by Tolkowsky ) are the most common. James Allen, the premier diamond retailer, offers four cuts of diamonds, two of which are ideal. A TrueHearts diamond is a type of ideal cut diamond.
Hearts and Arrows
The term Hearts and Arrows (often abbreviated H&A) refers to round brilliant diamonds that have been cut to a very high degree of three dimensional symmetry, also referred to as “optical symmetry” or “optical precision”. Hearts and Arrows Diamonds examined in a special reflector device will show a distinct pattern of 8 arrows when viewed from the top, and a pattern of 8 distinct hearts when viewed from the bottom.
It is very difficult for the diamond cutter to achieve the level of precision necessary for hearts and arrows as it requires more skill, more time, and the loss of more weight from the original diamond rough. For these reasons H&A diamonds are significantly more costly to produce. Achieving optical symmetry requires an exacting process of making sure all of the tiny facets line up perfectly against their counterparts on the opposite side of the diamond. Only when a diamond is crafted so that each facet is in alignment with its corresponding facet in three dimensional space, will a well-defined pattern of hearts and arrows be displayed. Therefore, true Hearts and Arrows patterning is visual evidence of precision craftsmanship that has the potential to maximize light performance. The benefits of H&A diamonds extend well beyond the patterns themselves.
Below we will present detailed information about hearts and arrows diamonds including how the patterns are formed and how they are analyzed. For those more interested in understanding what this all means from a consumer’s standpoint, please see our page on the benefits of H&A diamonds.
Ideal Cut And Hearts And Arrows
It is natural to associate hearts and arrows with ideal cut diamonds, but the two do not always go hand in hand. In fact, ideal light performance and optical symmetry are related but separate qualities. They can be thought of generally as proportions and precision. It is true that H&A patterns are only achievable through a relatively narrow range of proportions, most of which will result in good light performance. And while the level of craftsmanship required to create H&A is also an indication that a cutter is aiming for top performance, it is quite possible to achieve optical symmetry in a diamond with less than optimal proportions. Some proportion sets can result in light leakage and other performance deficits, even when optical precision is excellent. Achieving both simultaneously is the concept behind the “super ideal”.