Diamond Grading

Diamond grading, grading reports, cut grades and terminology.

Diamond grading reports are invaluable documents that show in detail a diamond's credentials. They provide a unique fingerprint of a diamond which is a source of vital information to the trained gemologist, jeweler or consumer. A diamond Grading Report will contain a complete quality description of the diamond and will include information on shape, weight, clarity, fluorescence, color grade, measurements, and proportions and finish grade. It will also confirm to that the stone is indeed the genuine article. A Diamond Grading Report enables you to buy your diamond with confidence.A diamond grading report, however, is only useful if it is reliable and has been issued by a reputable independent laboratory which has no financial interest in the stone. Purchasers can feel confident that their diamond is indeed of the quality Union Diamond represents. An independent gemological laboratory with skilled gemologists who use specialized equipment to measure and evaluate each diamond's particular characteristics and attributes. This information is provided in written form and is called a diamond grading report or diamond quality document (and is commonly referred to as a certificate).

In most cases, a diamond grading report will accompany any of our loose diamonds. The most common will be a Gemological Institute of America (GIA), an American Gem Society (AGS), an International Gemological Institute (IGI), Hoge Raad voor Diamant / Diamond High Council in Antwerp, Belgium (HRD), the EGL USA Gemological Laboratory (EGL USA) and the EGL International Laboratory (EGL Intl). These laboratories are recognized world over and are totally independent of Union Diamond. We do not warrant or guarantee the accuracy of their grading and these reports are provided only as a courtesy. Union Diamond does not grade diamonds and relies solely on the issuing laboratory. When evaluating diamonds, please take into consideration the grading in the context of the issuing laboratory and the standards each lab applies while determining grade. Diamond grading is subjective and methods of grading by the different laboratories and different graders may have very different opinions as to grade. Union Diamond cannot be held liable for those circumstances. Union Diamond does not warrant the accuracy of any information contained in any third-party laboratory grading report, or in any information we provide to you derived from any such laboratory grading report.

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A grading report also contains the stone's color grade. A diamond's color is evaluated by comparing it to the Gemological Institute of America's color scale, which is based on a set of diamonds of known color. Its grade is listed as a letter of the alphabet from D through Z, with D being the most colorless and having the highest value and Z being yellow in color and having the lowest value. It also lists the diamond's clarity, an evaluation of any natural blemishes or inclusions the stone may have inside or on its surface. The type and location of these blemishes determines the clarity grade, and therefore its value.

The carat weight of the diamond will also be listed on the grading report, rounded to the nearest hundredth of a carat (for example 1.05 ct, 0.95 ct, etc.) The diamond's measurements will also be indicated in millimeters. A grading report also includes a plot that "maps" the diamond's inclusions. These may be listed as "crystals", "feathers", "pinpoints", "naturals", "scratches" and "clouds" among others. Since each diamond is unique, the diagram acts like a fingerprint to identify that particular diamond. A diamond can be compared to its report by examining it under a 10-power loupe.

All jewelry items unless accompanied by Lab Grading Reports are considered "graded as mounted". Grading diamonds while mounted is particularly difficult. A Graduate Gemologist will examine the item and will, to the best of their ability, make a judgment based on their opinion and training as to the grade.

Diamond shape, size and quality shown in our jewelry and diamond images are representations only. They are not the actual stone or jewelry item you are purchasing. Jewelry items with more than a single stone are graded and sold based on “Average Color” and “Average Clarity”. We determine “Average” based on approximating the statistical norm or average or expected value of the entire pre-set item. All images used on this website are enlarged to show detail.

Not all laboratories grade a diamond's cut or describe the nature of the diamonds inclusions or characteristics. You will, however, find information on its depth and table percentages, girdle thickness, as well as general comments on the stone's polish and symmetry. The AGS does provide an evaluation of a diamond's cut, listed on a scale from 0 to 10, with 0 being cut to 'ideal' proportions and 10 being cut to less-than-ideal. Other laboratories may list the cut as "Excellent", "Very Good", "Good", "Fair" or "Poor". Union Diamond also classifies a diamond by its cut. Union Diamond classifies cut within the following ranges; Select Ideal?, Premium, Very Good, Good and Fair. These cut grades represent Union Diamond's opinion at the time of sale only after review of certain characteristics, measurements and percentages. Union Diamond may also use terminology that is commonly used within the diamond industry. Such comments may include the terms beautiful, eye clean, face up. These terms are used in conjunction with industry best practices but are referred to as an opinion only. These opinions may change from time to time based on changes in grading techniques, equipment and interpretation. Diamond grading is subjective and a customer should always consult the grading certificate as the only source of fact as opinions can and do change from one representative to another as they do from one jeweler to another.

By purchasing from Union Diamond, you fully understand that under no circumstances shall Union Diamond be liable for any indirect, special, incidental or consequential damages of any kind, regardless of the form of action, whether in contract, tort (including negligence), strict product liability or otherwise, even if we have been advised of the possibility of such damages.