Jewelry and Diamonds The Buying Guide: Diamond Grading Report

Today, few fine diamonds over one carat can be bought without a diamond grading report, or certificate, as they are also called, from a respected clinical. Reports Scottsdale diamonds issued by the GIA/Gem trade clinical are most common in the united states and many countries around world.
A grading report does more than clarify the stone’s genuineness, it fully describes the stone and evaluate all of the critical factors influencing quality, beauty, and value. Grading reports can be very for a variety of reasons. The information they contain can provide proof of the “facts” as represented by the seller and enable one to produce a safer decision when purchasing a diamond. Another, important function of reports is to verify the identity of a specific diamond at some future time, if, for example, it has been out of one’s control for any reason. For insurance purposes, the information provided on the report will help ensure replacement of a lost or ripped off diamond with one that is actually “compatible quality. inches

Reports are not necessary for every diamond, and many beautiful diamonds used in jewelry can be bought without them. But when considering the purchase of a very fine diamond weighting one carat or more, we strongly recommend that the diamond be plus a report, even if it means having a diamond taken from its setting (no reputable lab will issue a report on a mounted diamond), and then reset. If you are considering a diamond that lacks a report, it is simple for your jeweler to obtain one. Or, now that GIA is providing diamond grading reports to the public, you may submit a diamond at GIA yourself.

Do not rely on the report alone

The availability and widespread use of diamond grading reports can, when properly understood, enable even those without professional skills to make valid comparisons between several pebbles, and thus make more informed buying decisions. Reports can be an important tool to help you understand differences influencing price. But we must caution you not to let them affect what you like or really want. Remember, some diamonds are very beautiful even though they don’t adhere to establish standards. In the final analysis, use your own eyes and enquire yourself how you like the stone.

Complaintant who was trying to decide between several diamonds. Her husband wanted to buy her the stone with the best report, but she preferred another stone which, according to what was on the reports, had not been nearly as good. They decide up against the best diamond and bought one that made her happiest. The important thing is that they knew exactly what we were holding buying, and paid an appropriate price for that specific combination of quality factors. In other words, they made an informed choice. The reports gave them assurance from what facts, and greater confidence that they knew what we were holding really comparing.

Improper use of reports can lead to costly mistakes

As important s diamond grading reports can be, they can also be taken advantage of and lead to untrue final thoughts and costly mistakes. The key to being able to rely on a diamond report, and having confidence in your decision, lies in understanding to learn it properly. For example, when trying to decide between two diamonds accompanied by diamond grading reports, buyers all too often make a decision by comparing just two factors looked at on the reports, color and clarity, and think they have made a sound decision. This is rarely the case. No one can make a sound decision based on color and clarity alone. In fact, when significant price differences exists between two pebbles of the same color and clarity as the more expensive stone, and often it is not the better value. Having the same color and clarity is only area of the total picture. Differences in price indicates differences in quality, differences you may not see or understand. With round diamonds, the information you need is on the report, but you must understand what all the information means one which just make valid comparisons.

A word of caution: Do not make a purchase relying solely on any report without making sure the report matches the diamond, and that the diamond is still in the same condition described. Always seek a professional gemologist, gemologist-appraiser, or gem-testing clinical to confirm that the stone enclosing report is, in fact, the stone described there, and that the stone is still in the same condition indicated on the report. There are instances where a report has been accidentally sent with the wrong stone. And, in some cases, chat fraud is involved.

How to read a diamond grading report

Check the date issued. It is very important to check the date on the report. It’s always possible that the diamond has been damaged since the report was issued. This sometimes occurs with diamonds sold at auction. Since diamonds can become damaged or broke with wear, one must always check them. For example, you might see a diamond plus a report describing it as D : Immaculate. If this stone were badly damaged after the report was issued, however, the clarity grade could easily drop to VVS, and in some cases, cheaper. Needless to say, when this happens value would be dramatically reduced.

Who issued the report? Check the name of the clinical providing the report. Is the report from a clinical that is known and respected? If not, the information on the report may not be reliable. Several well-respected laboratories issue reports on diamonds. The best known in the united states have the Gemological Institute of America Treasure Trade Clinical (GIA/GTL or GIA), and the American Gemological Laboratories (AGL). Respected Eu labs providing reports have the Belgian Diamond High Authorities (HRD). Regardless of which report you are reading, all will provide similar information, including:

Identity of the stone. This confirms that the stone is a diamond. Some diamond reports don’t make a specific statement about identity because they are called diamond reports and are only issued for genuine diamonds. If the report is not called a “diamond grading report” then the converter should have a statement attesting that it is genuine diamond.

Weight. The carat weight must be given.

Dimensions. Any diamond, of any shape, should be measured and the dimensions recorded as a method of identification, particularly for insurance/identification purposes. The dimensions given on a diamond report are very prices and provide information that is important for several reasons. First, the dimensions can help you determine that the diamond being examined is, in fact, the same diamond described in the report, since it is likely that having two diamonds with exactly the same carat weight and millimeter dimensions is remote. Second, if the diamond has been damaged and re-cut since the report was issued, the millimeter dimensions may provide a hint that something has been altered, which might affect the carat weight as well. Any discrepancy between the dimension that you or your jeweler make do measuring the stone, and those provided on the report, should be a red flag to check the stone very carefully.

Finally, the dimensions on the report also tell you whether the stone is round or out of round. Out of round diamonds sell for less than those that are more perfectly round.

Fine diamonds are “well-rounded”.

The diamond’s roundness will affect value, it’s the same determined very carefully from measurements of the stone’s diameter, gauged at several points around around the circumference. For a round diamond, the report will most likely give two diameters, measured in millimeters and noted to the hundredth: for example, 6. 51 rather than 6. 5; or 6. 3 years ago rather than 6. 0. These indicate the highest and lowest diameter. Diamonds are very rarely perfectly round, which is why most diamond reports will show two measurements. recognizing the rarity of truly round diamonds, some deviation is permitted, and the stone will not be considered “out of round” unless it deviates by more than the established typic, approximately 0. 10 millimeter in a one carat stone. In a one carat diamond, if the difference is 0. 10 or less, then the stone is considered “round. inches If the difference is greater, it is “out-of-round. inches

To calculate a satisfactory deviation on a particular stone, average the high and the low diameter dimension given and multiply that number by 0. 0154. For example, if the dimensions given are 8. 20x 8. 31, the diameter average is 8. 25 ( (8. 20 + 8. 31)/2). Multiply 8. 25 by 0. 0154 = 0. 127. This is the acceptable deviation allowed for this stone (between 0. 12 and 0. 13). The actual deviation in this example would be 0. 11 (8. 31 : 8. 20), well within the patience, and this diamond would be considered “round. inches Some flexibility is permitted on diamonds over two carats.

Depending on degree of out-of-roundness (how much it deviates from being perfectly round), price can be affected. The greater the deviation, the cheaper the price should be.

Dimensions for fancy shapes

While dimension for fancy shapes diamonds are not as important as they are for round diamonds, there are length to width ratios that are considered “normal” and deviations may result in price deals. The following reflect acceptable ranges:

Pear shape: 1. 50: 1 to 1. 75: 1

Marquise shape: 1. 75: 1 to 2. 25: 1

Bright green shape: 1. 50: 1 to 1. 75: 1

Square shape: 1. 50: 1 to 1. 75: 1

To raised understand what this means, let’s look at a marquise diamond as an example. If its report showed the length to be 15 millimeters and the width to be 10 millimeters the length to width proportion would be 15 to 10 or 1. 5: 1. This would be acceptable. If, however, the dimensions were 30 mm long by 10 mm wide, the proportion would be 30 to 10 or 3: 1. This would be unacceptable; the proportion is too great, and the result is a stone that looks much too miss its width. Note: A long marquise is not necessarily bad, and some people prefer a longer shape, but it is important to understand that such pebbles should sell for less than include those with normal extent. Always keep in mind the length to width proportion of fancy cuts, and adjust the price for that are not in the acceptable range.

Evaluating proportioning from the report

As discussed earlier, good proportioning is usually as critical to diamond as it is to the man or woman who dons it! The proportioning, especially the depth percentage and table percentage, s what determines how brilliance and fire the stone will have.

The information provided on diamond reports pertaining to proportions is critically important for round, brilliant cut diamonds. Unfortunately, it is only of minimal use with fancy fancy shape diamonds. For fancies, you must learn to rely on your eye to tell whether or not the proportioning is acceptable: are there differences in brilliance across the stone? Or flatness? Or dark spots such as “bow-ties” resulting from poor proportioning.

Evaluating the proportioning of a diamond is usually as critical as evaluating the color and clarity grades. Diamonds that are cut close to “ideal” proportions, pebbles with “excellent” makes can easily cost more than typical while diamonds with poor makes sell for less; very badly proportioned pebbles should be priced for much less. The information on a diamond report can help you evaluate the proportioning and know whether or not you should be paying more, or less, for a particular diamond.

Depth percentage and Table percentage key to beauty

To determine whether or not a round stone’s proportioning, so critical to its beauty, is good, look at the section of the report that describes depth percentage and table percentage. The depth percentage represents the depth of the stone, the distance from the table to the culet, as a percentage of the width of the stone. The table percentage represents the width of the table as a percentage of the width of the entire stone. These numbers indicate how well a round stone has been cut in terms of its proportioning, and must adhere to very precise standards. Your eye may be able to see differences in sparkle and brilliance, but you may not be able to discern the subtleties of proportioning. The proportions on the report should fall within a fairly specific range in order for the stone to be judged acceptable, excellent, or poor.

Some reports also provide information about the crown angle. The crown angle informs you the angle at which the crown portion has been cut. This angle will affect the depth and table percentage. Normally, if the crown angle is between 34 and 36 degrees, the table and depth will be excellent; between 32 and 34, good; between 30 and 32 degrees, fair; and less than 30 degrees, poor. If the exact crown angle is given, it is probably considered acceptable. If not, there is a statement indicating that crown angle is greater than 36 degrees, or is less than 30 degrees.

Depth percentage

A round diamond cut with a depth percentage between 58 and sixty-four percentage is generally a lovely, lively stone. You should note, however, that girdle thickness will affect depth percentage. A high depth percentage could result from a thick or very thick girdle, when checking depth percentage on the diamond report, check the girdle information as well.
Pebbles with a depth percentage over 64% or under 57% will normally be too deep or too ” light ” to exhibit maximum beauty and should sell for less. If the depth percentage is beyond their budget, the stone can look smaller than its weight indicates. If the depth percentage is exceptionally high, brilliance can be significantly affected. Diamonds that are so ” light “, that is, pebbles with such low depth proportions, they own no brilliance and liveliness at all. When dirty, such pebbles look no better than a piece of glass.

We avoid diamonds with depth proportions over 64% or under 57%. If you are attracted to such diamonds remember that they should sell for much less per carat.

Table Percentage

Round diamonds cut with tables ranging from 53% : 64% usually result in beautiful, lively pebbles. Diamonds with smaller tables usually exhibit more fire than include those with larger tables, but pebbles with larger tables may have more brilliance. As you see, table width affects the diamond’s personality, but deciding which personality is more desirable is a matter of personal taste.


Under finish on the diamond report, you will find an evaluation of the diamond’s improve and symmetry. Improve serves as an indicator of the care taken by the cutter. Products you can the stone’s improve is a factor that can’t be ignored in evaluating the overall quality of a diamond, as well as its cost and value. Improve can be described on the report as excellent, very good, good, fair, or poor. The price per carat should be less on diamonds with “fair” or “poor” improve. Cost per carat is usually more for diamonds that have “very good” or “excellent” Improve.
Symmetry describes several factors:

How the side edges arrange with one another;
whether or not the facets collected from one of side of the diamond match matching facets on the opposite side;
whether or not facets in the top component to the diamond are properly lined up with matching ones in the bottom portion.

When the symmetry is called “fair”, or worse, something is out of line.
When evaluating symmetry, the most important area to check is the conjunction of the crown (top) to the pavilion (bottom). If it is negative, it will make a visual difference in the beauty of the stone, and correspondingly in its price. To check for proper conjunction here, simply look at the diamond from the side to see whether or not the facets just above the girdle arrange with the facets just beneath the girdle.

When the top and bottom facets do not get in line, what this means is sloppy cutting and, more important, the overall beauty of the diamond’s is decreased. This will reduce the price more than other symmetry faults.

How does the girdle affect value?

The girdle is another important item described on diamond grading reports. The report will indicate whether or not the girdle is rubbed, or faceted, and how thick it is. Girdle thickness ie very important for two reasons:

It affects value, and
It affects the diamond durability.
Girdle thickness ranges from extremely thin to extremely thick. Diamonds with girdles that are excessively thin or thick normally sell for less than other diamonds. An extremely thin girdle enhances the risk of chipping. remember that despite their legendary firmness, diamonds are brittle, so very thin edge postures a greater risk.

If a diamond has an extremely thick girdle, its cost should also be reduced somewhat because the stone can look smaller than another diamond of the same weight with a more normal girdle thickness. This is because excess weight is being consumed by the thickness of the girdle itself.
There are some cases where a very thick girdle is acceptable. Shapes that have several points, such as the pear shape, heart, or marquise, can have thick to very thick girdles in section of the points and still be in the acceptable range. Here the excess thickness in the girdle helps protect the points themselves from chipping.

Generally, a diamond with an extremely thin girdle should sell for less than one with an extremely thick girdle because of the diamond’s increased vulnerability to chipping. However, if the girdle is much too thick (as in older diamonds), the price can also be even less because the stone cam look significantly smaller than other diamonds of comparable weight.

The Culet

The culet looks like a spot towards the end of the diamond, but it is generally another side, a small, flat improve surface. This side should be small or tiny. A small or tiny culet won’t be noticeable from the top. Some diamonds, today, are specific. This means that there really is no culet, that the stone has been cut along to a point instead. The more expensive the culet, the more visible it will be form the top. The more visible, the cheaper the cost of the diamond. Diamond called having large or “open” culet such as old Eu or old-mine cut diamonds are less desirable, because the appearance of the culet causes a reduction in sparkle or brilliance at the very center of the stone. These pebbles normally need to be re-cut, and their price should take the necessity for re-cutting. for the same reasons, a damaged or broken culet will seriously deter from the stone’s beauty and significantly reduce the cost.

Color and Clarity

The color and clarity grades on a diamond report are the items most people are familiar with. They are important factors in terms of determining the value of a diamond, but as the prior discussion has shown, they cannot tell the whole story about the diamond.

A word about fluorescence

Fluorescence, if present, will also be indicated on a diamond grading report. It will be graded weak, moderate, strong, or strong. Some reports indicate the color of the fluorescence as blue, yellow, white, and so on. If fluorescence is moderate to strong and the color is not indicated, you should ask the jeweler to tell you what color the stone fluoresces. A stone with strong yellow fluorescence should sell for less since it will appear more yellow than it really is when worn in sunlight or fluorescent lighting. The presence of blue fluorescence will not deter, and in some cases may certainly be a bonus since it will make the stone appear more white than it really is in sunlight or fluorescent lighting. However, if the report show a very strong blue fluorescence, there may be an oily or milky appearance to the diamond. If the stone appears milky or oily to you as you consider it, especially in sunlight or fluorescent light, it should sell for less.

Pay attention to the full clarity picture provided

The placement, number, type, and color of internal and external flaws will be indicated on a diamond grading report, can include a plotting, d diagram showing all the information. Be sure you carefully note all the information in addition to the cumulative grade. Remember, the keeping of defects make a difference value.

A steady diamond grading report cannot be issued on a fracture-filled diamond, so GIA and most other labs will not issue a report on diamonds which were clarity enhanced by this method. The diamond will be returned with a notation that it is filled and cannot be graded. Reports are issued on diamonds which were clarity enhanced by laser. Remember, however, that no matter what the clarity grade, a lasered diamond should not cost less than another with the same grade.

A last word about diamond reports

Diamond grading reports provide a very useful tool to support in comparing diamonds and evaluating quality and value. But the key to their usefulness is proper understanding of how to read them, and how to look at the stone. Those who take the time to learn and determine what they are reading and, therefore, what they are really buying, will have a major advantage over those who do not.

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