How to Read a GIA Diamond Grading Report

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So you’re ready to propose to the love-of-your-life with a Knox Custom Engagement Ring, but you want to be positive you’ve chosen the best possible diamond. Knox Jewelers recommends selecting a diamond evaluated by GIA to ensure the diamond comes with a detailed graded report. A GIA Diamond Grading Report is the standard for evaluating diamonds and their quality. Don’t know how to read a GIA Diamond Grading Report? Don’t worry, Knox will always help you learn everything about your diamond selection, either in-store or online.

GIA stands for Gemological Institute of America. It is a public and independent benefit institute that was established in 1931. They are the leading source of knowledge, standards, and education when it comes to gems and jewelry. GIA is the creator of the “4 Cs” (Color, Clarity, Cut, and Carat Weight) and the International Diamond Grading System that maintains the methods and best practices for describing diamond quality. Today, virtually everyone in the international diamond industry uses these methods for comparing and evaluating diamonds. A grading report from GIA is more than a collection of observations about a gem. It represents an accurate and unbiased, comprehensive scientific investigation.

Let’s review the main components of a GIA grading report.

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Each diamond evaluated by GIA is assigned a unique GIA Report Number which you can use to look up your report online.

A diamond’s Shape refers to its face-up outline.  Popular shapes include round, square, oval, rectangle and pear.

Cutting Style refers to a stone’s faceting pattern. Brilliant-Cut diamonds contain a large number of small, triangular shaped facets. These include Round Brilliant, Princess and Ovals cut gems. Step-Cut diamonds contain larger, long, rectangle shaped facets.  These include Emerald and Asscher cut gems.

A diamond’s Measurements will be listed in the order of smallest width, largest width and height.

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The Weight of a diamond is measured in a form called carats. GIA reports a diamond’s carat weight to the nearest hundredth of a carat. To give you some perceptive, 1 carat is equal to 0.20 grams.

The GIA Color Grade system describes the diamond’s lack of color by ranging from the denotation D, which is colorless, all the way to Z, which will be a shade of either light yellow or brown. Color grades from D to F are considered colorless diamonds and G to J are near-colorless.

Diamond Clarity evaluates the size, the number, relief, nature, and position of internal inclusions and surface blemishes. The Institute assigns one of eleven clarity grades to a diamond. This can range from the clarity grade of flawless to that of included and lists the most prominent clarity characteristics. Stone graded VS2 and above should be eye-clean, with inclusions only seen under magnification.

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On some report formats, Clarity Characteristics are shown as a plotted diagram, marking significant or identifying characteristics. A key lists the relevant symbols and their definitions. Red symbols stand for inclusions, which characteristics inside a stone. Green or black symbols stand for external characteristics on the diamond, or blemishes.

For the standard round brilliant diamond, GIA assigns a Cut Grade ranging from Excellent to Poor. Diamonds can be Excellent, Very Good, Good, Fair, or Poor. This grading takes into account seven components; Polish, Symmetry, Weight Ratio, Durability, Brightness, Fire, and Scintillation.

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The diamond’s Proportions are thoroughly described as well, from its shape and cutting style to its precise measurements. A diagram will show you the diamond’s profile as well as its dimensions.

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A description of Fluorescence is provided as an additional identifying characteristic. GIA tests every diamond to ensure that it is natural and to identify any processes that may have been used to alter its color or clarity. An asterisk next to the color or clarity grade indicates that the diamond has been treated. Treatments and additional identifying characteristics are described in the comments section.

If the diamond is inscribed, the Inscription will be noted on the report as well. A GIA Grading Report has a number of sophisticated security features designed to ensure its authenticity and integrity. They offer a variety of diamond reports, among them the Diamond eReport, an interactive online option available only for natural and untreated diamonds(perfect if you want to search for beautiful custom diamond engagement rings from the comfort of your home). The Institute operates under strict standard procedures and principles designed to ensure objectivity and accuracy, no matter which report you receive.

That’s how to read a GIA Diamond Grading Report! It’s not as intimidating as you might think. Selecting the perfect ring among many beautiful custom diamond engagement rings might be another story. Luckily, Knox Jewelers can help you look at a variety of rings and narrow it down to the perfect one for your lucky life partner. GIA Diamond Grading Reports are also available! Let Knox Jewelers help you learn about diamonds so you can pick the perfect diamond that meets the color, clarity, cut, and carat weight that you desire and help give your engagement a beautiful start.

Clarity grades… the dirty little secret

Are all SI-1 clarity diamonds eye-clean?
Are all SI-2 clarity diamonds eye-clean?
Are all VS-2 clarity diamonds eye-clean?
Are all VS-1 clarity diamonds eye-clean?

The truth may surprise many… but the answer to all four of the above questions is, no.

Here is another thought for those considering ‘buying blindly’ from the virtual list of diamonds available on the internet.

Many consumers assume that all clarity grades are uniformly identical or at least very close, Eg. “All SI-1 clarity diamonds will be eye-clean” at least all the SI-1 diamonds from the preeminent labs.

Nothing could be further from the truth, especially in the SI grades.

SI clarity stones of the same grade can vary tremendously, from eye-clean to easily visible to the naked eye. (see photo below of three actual stones, all with a Gemological Institute of America (GIA) clarity grade of SI-1)

It is helpful to think of the clarity grades as a range, and not an exact, precise, quantifiable term.

Within these ranges of clarity there are for example, good SI-1’s, bad SI-1’s and maybe even the ugly SI-1’s. ( this analogy will hold true thru the other clarity ranges as well)

It is common sense that diamond sellers that stock diamonds will buy for their own stock the nicer of these ranges of clarities and especially the nicer (eye clean) SI’s .

With the diamond sellers that stock diamonds buying only the ‘good’ SI diamonds for their stock, this of course leaves the bad and the ugly to be sold elsewhere.

Think about it.

verical%20clarity%20shot Diamonds

On this very topic, here is an inquiry from a  poster on an online diamond forum and my reply to the poster. He was asking if the SI-1 diamond he saw listed on a “virtual listing venue” was a good deal.

I’ve been looking to buy an engagement ring online, and have come to the conclusion has the best prices out there. For instance:

Price: $xxxx.xx

Stone shape: Round
Carat Weight: 0.91 carats
Cut: Ideal
Color: G
Clarity: SI1
Certificate type: GIA
Depth %: 62.8
Table %: 58.0
Symmetry: Very Good
Polish: Very Good
Girdle: Thin to Medium – Faceted
Culet: None
Fluorescence: None
Measurements: 6.22 x 6.16 x 3.89 millimeters
Length-to-width ratio: 1.01

To which I replied:

Hi, Welcome to the forum.

The short answer is, if the diamond is a strong SI-1 and not overly dark or dead from being marginally deep… the stone may be well priced.

The longer answer and the reality of the situation is that diamonds are essentially priced by the marketplace and by how strictly graded any particular diamond is and of course that particular diamonds cut quality.

I will only speak to the subject of clarity, but rest assured that the same market forces will affect the desirability and saleability of any diamond with regard to the diamonds Color and make and/or overall finish.

There are varying levels of SI-1 clarity diamonds (other clarities as well) and they are all priced by the supply and demand forces of the marketplace based on how strictly graded the diamond is.

Do a little research on clarity and you will find that SI-1 stones can vary from ‘clean to the naked eye’ to having ‘easily noticeable inclusions’

The diamonds on ____ ____ and many other websites are from virtual lists, these are lists of diamonds owned by cutters and wholesalers, bear in mind that most if not all of these same diamonds are available to jewelry stores and other volume buyers of diamonds but for whatever reason have gone unsold.

Of course, the most obvious and common reason for diamonds to be rejected by expert buyers is that the diamond is not strictly graded (IE. not a strong SI-1)

Certainly, there can be quality diamonds on these virtual lists also.

However, it is common sense that the longer any one diamond stays on this list, especially if it is priced ‘competitively’ the more likely it is that this particular diamond is a reject of the expert buyers that comprise the market.

Unfortunately, there is no way for consumers to tell how long a diamond has been on the market.

Consumers do not have the beneficial market forces to help the non-experts as one would have in another marketplace such as real estate, where an overpriced piece of real estate that has been on the market for years/months raises obvious red flags.

Aaaahhh… so where do these ‘rejected’ diamonds end up?

What better venue for a seller of such a stone than to be able to sell it to a consumer, sight unseen. Think about it.

His shopping is done… she has a ring on her finger… a wholesaler has sold a diamond that experts would not buy… and yet everybody is happy ?

Yes, and it is because all diamonds are beautiful, this is especially true for diamonds sold on the internet as there are not other more beautiful diamonds to compare it to. Even diamonds with noticeable imperfections in say, 3% of the visible area of the diamond may sparkle beautifully in the other 97 % of the diamond.

So… the diamond now has a happy home due to the above reason, but not without considerable help from the cognitive dissonance (the tendency in human nature to rationalize bad decisions) making this person think that his SI-1 diamond is the same as any other SI-1 diamond or that he has somehow found the deal of the century.

Speaking of which, there appears to be no shortage of people that seem to think they can swim with the sharks and out smart this ‘market place’ comprised of diamond buying experts and corporations that trade in diamonds for a living.

Hmmm? That last paragraph actually has the making of another article.

Brian Knox
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