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GIA vs GGS (Which Diamond Grading Lab is Best?)

Trying to decide between GIA and GGS diamond grading? We can confidently help you with that!

Many decades ago, jewelers and diamond dealers used to have no standardized way to determine the value of a diamond based on its color and its clarity. That meant the value of a particular stone was oftentimes the personal and subjective opinion of the dealer, which led to disputes between diamond dealers.

That's where diamond grading labs come into play; A reputable lab creates an objective, reliable way to assess true value across an entire market.

But not all labs are creates equal!

This quick guide will tell you everything you need to know about how GIA compares to GGS.

GIA vs GGS: The Short Answer

GIA and GGS are both diamond grading labs, but they are not at all equal. The GIA is generally accepted as an authoritative, accurate source of determining diamond value. The GGS is a lab run by industry professionals, but its assessments are almost never taken into consideration for determining diamond value in the market.

That's the short and sweet. A GIA grading will always be considered by diamond dealers to be a true indicator of a diamond's value, while a GGS grading will be disregarded by almost everyone in the diamond business.

At Honey, we proudly opt for GIA assessments as the gold-standard for the diamonds in our jewelry. Whether you're looking at our custom engagement ring lines or our wedding band lines, you'll find GIA certifications all over.

Our leadership even puts its money where its mouth is by having earned the certifications of GGGJ & AJA from the GIA.

We'll get a little further into the details so you fully understand the key differences between these two labs.

GIA Diamond Grading Reports and the Four Cs

To solve this problem, in 1953, the Gemological Institute of America (GIA), a nonprofit educational and research institute devoted to the study of gems, began to issue the first diamond grading reports. These reports used a system of grading diamonds newly invented by the GIA that you have probably heard of: the “Four C's.”

The Four C's stand for Color, Clarity, Cut, and Carat. With the introduction of this grading system in 1953, the GIA revolutionized the diamond industry and standardized the grading of diamonds.

For a good example of what the Four C's look like in the real world, check out our diamond finder tool. It gives you 360-degree closeup views of actual diamonds to choose from. This makes it easy for our clients to pick the exact diamond they want while having full confidence that they're getting a great stone.


The color evaluation of a diamond is determined by the absence of color. A diamond which is structurally perfect and chemically pure will have no color, no hue whatsoever, similar to a drop of pure water. Thus, a diamond with no color will have a higher value than a diamond with a bit of color.

The color grading scale goes from “D” to “Z,” with “D” being the highest grade and “Z” being the lowest grade. A completely colorless diamond will have the highest grade, “D,” and an increasing level of color will be accorded a lower grade.

The distinctions in color are oftentimes so subtle as to be unnoticeable to the untrained eye. But such color distinctions, though seemingly invisible to the naked eye, can mean a drastic difference in terms of the price and the quality of a diamond.


Because natural diamonds are formed through the process of carbon undergoing extreme pressure and heat deep below the surface of the earth, these diamonds can sometimes have external characteristics known as “blemishes” and internal characteristics known as “inclusions” as a result of the process of their formation.

The clarity of a diamond is determined by evaluating the number, relief, size, position, and nature of these internal and external characteristics, in addition to how these blemishes and inclusions affect the appearance of the diamond overall. The fewer inclusions and blemishes a stone has and the less the overall appearance is affected, the more valuable the diamond.

The grades of diamond clarity are divided into six categories which are then subdivided for a total of eleven specific clarity grades. The six categories and their subcategories are (in order of highest grade to lowest grade): Flawless (FL), Internally Flawless (IF), Very, Very Slightly Included (VVS1 and VVS2), Very Slightly Included (VS1 and VS2), Slightly Included (SI1 and SI2), and Included (I1, I2, and I3). So the highest clarity grade possible is FL and the lowest is I3.

 Blemishes and inclusions are oftentimes too small to be seen by those who are not practiced in grading and appraising diamonds. To the untrained eye, a VVS2 and an SI1 diamond might look identical, but the difference in clarity denotes a huge difference in terms of diamond price and quality. Expert assessment is thus extremely necessary.


The cut of a diamond is perhaps the most technically difficult and complex aspect to analyze. The cut grade denotes how well the facets of a diamond interact with light.

The cut evaluation takes into account brightness, fire, scintillation, weight ratio, durability, polish, and symmetry. The diamond is then graded Excellent, Very Good, Good, Fair, or Poor.


The carat weight of a diamond measures how much the stone weighs. One carat equals 200 mg. Each carat is subdivided into 100 points. This allows for exceedingly precise measurements.

If two diamonds have the same color, clarity, and cut grades but different carat weights, the heavier diamond is more valuable, since larger diamonds are rarer. But the overall determination of a diamond’s worth, value, quality, and price is determined by all four Cs, not just by one C.

Value of GIA Grading Reports

The four Cs and the diamond grading reports released by the GIA remain the gold standard for diamond grading to this day. GIA grading reports are accepted and respected the world over. Diamond markets around the globe trust diamond grades from the GIA more than grades from any other lab.

The GIA is known for having the highest and most consistent standards and is used more commonly than any other grading service.

Because the GIA is a nonprofit organization, it is not tied to or associated with any retailers or commercial gemstone dealers. Thus, the objectivity of the grades it gives is not affected by any potential financial benefit or profit, since there is none.

The GIA also has extensive safeguards ensuring that graders of diamonds remain thoroughly objective.

Diamonds graded by the GIA sell for the highest prices and are considered more valuable than diamonds without a GIA grading report. This is due to the consistency and irreproachable reputability of the GIA.

In fact, many reputable diamond dealers will sell only diamonds that possess a GIA grading report, since the grades of most other diamond grading laboratories are not generally considered reputable, valuable, or trustworthy.


Gemological Grading Services (GGS) is another diamond grading laboratory. This diamond grading lab is run by Thomas Jacobs, a master gemologist appraiser from Belgium who possesses more than 27 years of experience in the gem grading industry. He personally trains and oversees the appraisal team at GGS to use the most advanced tools and magnification.

Unfortunately, even with a high level of expertise, GGS possesses little to no reputation as a diamond grading lab in the eyes of the diamond market. If a diamond grading lab has no reputation, then its diamond grading reports are essentially worthless for consumers looking to protect their purchase.

Even if the gemologist running the lab knows what he is doing and can actually give a qualitative report of the diamond, the grades issued by his lab are worth almost nothing to the diamond market in general, because most gemstone dealers will not trust his grades due to his lack of reputation.

So the grade reports issued by Thomas Jacobs’ team at GGS may be legitimate, and they might actually give you a fair appraisal of the diamond in question. However, such a report does not mean much in terms of the overall monetary worth of the diamond, since an objective diamond dealer will not assign much value to a diamond grading report issued by GGS.

There are actually a surprising number of diamond grading laboratories that are not well-known or reputable. Most of these laboratories are run by a single gemologist or appraisal expert. No matter how honest, excellent, or experienced these experts may be, a grading report from one of these laboratories cannot be used to confirm the actual worth of a diamond.

The reports from any these labs would not be trusted or used by a professional to insure a diamond, compare the price of a diamond, or confirm the quality of a diamond.

One seeming advantage (and quite possibly the only advantage) that GGS has over GIA is the price of its services for smaller stones. For instance, a grading report on a stone weighing up to 0.69 carats costs $60 from GGS, while a grading report from GIA for a stone of that weight costs $64. A GGS report on stone weighing between 0.70 carats and 0.99 carats costs $65, while a report from GIA for a stone in that range costs $78.

Unfortunately, the GGS advantage ends there. Although using a report from GGS instead of a GIA report might save you $4 or $13, it is not at all worthwhile. Trying to save money by using a GGS report instead of a GIA report is a classic example of being penny wise and pound foolish. The GGS report will not be considered reputable and will not be thought of as a legitimate confirmation of the value of the diamond in question by a professional gemstone dealer.


We cannot in good conscience recommend the grading services of GGS, even though we trust that its organization is an honest one. The GIA is widely respected, and its reports are highly valued and considered the gold standard.

Another highly reputable, globally respected diamond grading lab is the American Gem Society Laboratories (AGS). If the diamond you are looking to buy possesses a GIA grading report or an AGS grading report, you can trust in the grades and thus the value of the stone in question.

However, a grading report from GGS, EGL, ADL, or any other such random diamond labs is worth basically nothing in the eyes of the diamond market. An appraisal from these labs will not do you any good in terms of determining the value of the diamond.

So in terms of GGS vs. GIA, honestly, there’s no comparison at all. The GIA is highly regarded, reputable, and worth your money (not to mention the fact that it invented the four C's), and the GGS is simply not worth your time or money.

If you have a diamond you wish to evaluate, pay a little more to seek the services of the GIA or AGS. Those reports will be well worth your time and money. And if you are buying a diamond, make sure the stone you purchase has a GIA or AGS grading report.

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