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Diamond grading is only valuable if you understand which lab provided the grading and how strictly or liberally they grade their diamonds. This article will help you avoid the labs that grade in misleading ways.

Which Grading Lab is Best For Lab Grown Diamonds? IGI or AGS are typically the best labs for grading lab-grown diamonds. While GIA is the most recognized and respected lab in the world for diamond grading, they aren’t the best option for lab grown diamonds. They don’t grade lab diamonds with the same level of detail that they grade earth mined diamonds.

There are many gem grading laboratories operating around the world. The pricing, reputation, grading detail, and the grading methodology varies widely between them. The rest of this article will help you understand some key differences and the lab that is likely best for grading your lab created diamonds.

Placing Trust in the Labs: Why Diamond Grading Matters

Diamond grading laboratories evaluate the gems that are sent to them and define key qualities of the stone they’re examining. When it comes to diamonds, they generally study and provide information in 4 primary areas. These are the 4 key drivers of diamond value—often referred to as the “4 C’s.” They include the following:

  • Color
  • Clarity
  • Cut
  • Carat Weight

Each of these areas are important aspects of value for both man made diamonds and earth made diamonds. Grading laboratories are staffed by professional gemologists we look to for clear and accurate information on the qualities of the gems that are sent to them.

Color is an evaluation of how vivid or colorless a diamond is. The diamonds at both of those extremes are typically the most prized (and expensive). Diamonds that are naturally colorless are rare and valuable. Most earth-grown diamonds have some degree of yellow or brown tint to them. The more hue of yellow or brown a nearly colorless diamond has, the less valuable it generally is (if all other variables being constant).

Again, it isn’t JUST colorless diamonds that are rare or highly sought after. Vivid colored diamonds are also quite rare and expensive. Diamonds can come in blue, yellow, green, red, pink, and many other colors. Some colors are more rare and valuable than others. Within its color group, the more deep and vivid the color of a particular diamond, the more valuable that it generally is.

Clarity has to do with the inclusions that a particular diamond has. It’s an evaluation of how many inclusions there are, how large they are, and where they’re situated in the gem. Because of size and positioning, some inclusions are more noticeable than others. Some can be easily observed with the naked eye, while others would require magnification to notice. In some cases, significant inclusions can even disrupt the flow of light within the stone, interfering with sparkle. Lab created diamonds often have inclusions in them—just like earth grown diamonds do.

Cut has to do with the quality of the facets that are created around the surface of the ring. The positioning and symmetry of the facets are a major consideration. The cut is both a science and an art. The ‘science’ behind it requires a certain number of facets of very specific sizes in carefully calculated positions around the ring. Again, symmetry is critical. With it, even an average diamond can sparkle and look beautiful. Without it, a beautiful can be left looking dull and lifeless.

Carat Weight means the actual weight of the diamonds, which is measured in a unit called carats—rather than something like ounces. Large diamonds are more scarce, so carat weight also is a driver of retail value. Generally speaking, the larger a particular diamond is, the more it’s going to cost.

Many labs also screen diamonds for an indication of possible diamond treatments that are designed to improve the appearance of the gem artificially—making it appear more rare and valuable than it actually is. The lab is on the lookout for things like HPHT (High-Pressure High Temperature) treatment, laser drilling, and fracture filling.

For the non-professional, the exact cut, color, and clarity qualities of the stone, along with their implications on value aren’t obvious. Determining if physical attributes are natural or the result of treatments is almost impossible, without looking for guidance and placing your trust in the hands of the professional gemologist that work at a grading lab. They have to help by establishing (or confirming) the quality factors, and characteristics, of their ring that determine rarity and value. That’s a lot of trust!

Based on the heavy responsibility that’s been placed on grading laboratories, you would hope that they would be fairly unified in the way that they grade diamonds. You would expect that the same diamond sent to multiple laboratories would receive a pretty similar grading report from each of them, but that’s not the case. In fact, their reports and grading can vary a lot from lab to lab—but why?

Some labs are used by jewelers because they grade more liberally. They essentially round up or are intentionally generous with their grading, the jewelers that sell these diamonds can attempt to sell them for more (as if they’re more valuable than they actually are). The nomenclature and scales also vary with some labs. Instead of using the standard terms and scales used by the largest and most respected labs, they use terms and scales that are far less clear—and often misleading. There’s a market for diamond graders that will tell their clients what they want to hear, rather than the actual facts regarding each gem.

Think about it this way, when a homeowner wants to sell their house, they may have an over-inflated and unrealistic impression of what it’s worth (or what they’d like to get for it). The first appraiser may not give them the value that they’d like to see attributed to their home, so they hire another—and another. Eventually, they find an appraiser that’s willing to get creative with the comparables that he pulls and how he interprets other similar homes that have sold. He gives them the value they were looking for, and they’re happy with the end result. The next time they have a home to sell, they’re likely to call the same appraiser.

Some small and unknown “Diamond grading companies” can be somewhat similar. Manufacturers and jewelers can probably find someone that will tell them what they want to hear if they look hard enough. Reputation is everything when it comes to the validity of diamond grading reports. The fact that a diamond was graded a certain way means almost nothing. The fact that it was graded by a well-respected lab like GIA (Gemological Institute of America), AGS (), or IGI (International Gemological Institute) means a great deal. In other words, a grading report, or certification, is only as good as the reputation of the company that created the report. If a jeweler shows a grading report for a diamond that was done by a lab that you’ve never heard of or don’t trust—seek confirmation regarding the features and quality of the diamond from a source you DO trust. Don’t make your buying decision based on the contents of a questionable report. Insist on confirmation through a reputable lab of your choosing.

The Domestic and International Labs That Grade Lab Created Diamonds

There are MANY gemological laboratories around the world. It’s a good idea to only work with those that are most trusted, reputable, and consistent. The labs listed below are some of those, serving various corners of the globe, that are often used for grading laboratory diamonds. Each lab has pros and cons. Some of those are major and some are minor. I’ll share more on those below.

  • GIA (Gemological Institute of America)
  • AGS (American Gem Society)
  • IGI (International Gemological Institute)
  • GSI (Gemological Science International)

GIA: Operates labs in Antwerp, Bangkok, Hong Kong, Mumbai, Surat, Tokyo, California, Gaborone, Johannesburg, Ramat Gan, New York City, and Carlsbad. They’re headquartered in Carlsbad, California.

AGS: Founded in 1996. AGS (whose labs are often referred to as AGSL) has fairly well-respected grading standards, but they only grade the cut on a small assortment of diamond shapes. They won’t grade most fancy colored diamonds. They won’t grade diamonds for the public. You have to submit your diamond for grading through a member jeweler. Unfortunately, those jewelers aren’t always nearby, and they mark up the cost of the service, which means that AGS grading often becomes a hassle and much more expensive for most lab diamond owners. AGS currently has a physical presence in Nevada, Israel, Belgium, India, China, and Hong Kong

IGI: Headquartered in Antwerp, Belgium founded in 1975, IGI has been around for a while and has both deep experience and relationships. They’re grading is clear and specific, and their services are convenient to access and reasonably priced, so they’ve become the most popular lab. In fact, they’re the second most well-known grading lab in the world (behind GIA).

IGI maintains a physical presence in New York, Hong Kong, Mumbai, Bangkok, Tokyo, Dubai, Tel Aviv, Toronto, Los Angeles, Kolkata, New Delhi, Thrissur, Jaipur, Surat, Chennai, Ahmedabad, Hyderabad and, of course, Antwerp. IGI is extremely popular across Europe and Asia. All of their international locations spread across those regions also makes them a convenient lab to get gems to.

GSI: This is a fairly new lab that is heavily used by large retail chains. They grade diamonds very quickly but have come to be known for loose grading standards. Retail chains that use them probably appreciate both their speed and their generous grading tendencies.

The BIG Differences Between GIA, IGI, and AGS When It Comes to Lab Diamonds

Each lab grades a little differently than the others. They each have their own criteria and set of standards for evaluating diamonds. For example, while GIA and IGI use a letter scale that runs from D through Z (‘D’ being the grade reserved for the most colorless diamonds) to assign a color grade to the diamonds they process, AGS uses a 0-10 scale (with ‘0’ assigned to the most colorless diamonds. This same 0-10 scale is also used to grade the cut and clarity of each diamond they evaluate. This difference in the way AGS reports their findings isn’t a problem, as long as you know how to translate the results. Click here to see an image that illustrates how the 0-10 AGS scale aligns with the scales that labs like GIA and IGI use to report on color, cut, and clarity.

GIA is the biggest name in the world of diamond grading, BUT they aren’t a good choice when it comes to lab-grown diamonds. That’s because GIA has decided not to grade lab-created diamonds the same way that they grade earth-grown diamonds. When it comes to identifying the color qualities of man-made diamonds, they provide only very general categories and terminology. For example, they may use the term ‘colorless’ to describe a diamond that falls somewhere in the D, E, F spectrum, or ‘near colorless to describe a GHI diamond.

That kind of generalization, just isn’t helpful, because an ‘E’ or an ‘F’ ISN’T colorless, and the distinction in color ABSOLUTELY WILL impact the gem’s actual value. The grading of clarity (inclusions) for lab diamonds is also much less detailed on GIA reports than it is for mined diamonds.

Today’s lab-grown diamonds can be made through two technologies, or processes (HPHT and CVD). GIA will grade HPHT diamonds, but they won’t grade CVD diamonds currently.

For all these reasons, GIA isn’t used very widely for the grading of man-made diamonds. Manufacturers and jewelers have been forced to find other providers that grade fairly and consistently.

AGS pioneered cut grading, but are only willing to grade a small variety of shapes currently. They also won’t grade most fancy colored diamonds.

As mentioned earlier, AGS only performs grading services for the approved member jewelers. For a jeweler to become an AGS member is not a fast or simple process, so it’s often difficult for AGS to be a considered a viable option—they just aren’t very accessible. Because all grading has to be submitted through jewelers that can mark up the cost of services, it’s unlikely that AGS grading will be very price competitive either. AGS is generally highly respected for their grading standard, but because of their structuring, they also aren’t very widely used for the grading of lab-created diamonds.

IGI has become the most common resource for those needing a well-known lab with a solid reputation and very detailed grading reports for lab diamonds.

What GIA, IGI, and AGS Grading Reports Cost

The cost of grading both earth-grown diamonds and lab-grown diamonds is determined by the gem’s weight. Labs typically won’t grade any gem that’s smaller than .15 carat. Grading mico-diamonds is too expensive to justify for most, and gauging the 4 C’s on a really tiny stone also proves challenging.

Grading reports include information on the measurements, carat weight, color, clarity, cut (& shape), polish, symmetry, and the fluorescence. The report can also include an inscription, comments section, report #, and a plot (or mapping) fo your gem,

IGI seems to grade the vast majority of the lab-grown diamonds that are produced around the globe. They’re used so commonly because they’re large and well known, because their rates are reasonable, and because their grading standards are respected. That’s not to say that jeweler or gemologist sings the praises of IGI (or any other lab for that matter), but well respected gemological organizations that have tested the grading results of many labs, and they’ve often been most impressed with the results of IGI, particularly when it comes to lab-grown diamonds, where GIA isn’t a reasonable alternative.

IGI Grading Fees (Full Report)

0.15 - 0.22$35
0.23 to 0.29$45
0.30 to 0.45$50
0.46 to 0.69$70
0.70 to 0.89$80
0.90 to 0.95$95
0.96 to 1.45$125
1.46 to 1.94$150
1.95 to 2.94$190
2.95 to 3.94$290
3.95 to 4.94$350
4.95 to 5.94$455

GIA’s prices are reasonable, and their grading record and reputation is rock solid, It’s only the general nature of their ‘Synthetic Diamond’ reports that keeps them from being a more viable option for grading lab cultured diamonds. If GIA ever changed their policies and started grading lab-made diamonds the same way they grade mined diamonds, they would almost certainly take over the majority of the grading done for lab diamonds too.

GIA Grading Fees (Full Report)

Size (in Carats)Cost
0.15 - 0.22$53
0.23 - 0.46$59
0.47 - 0.69$64
0.70 - 0.99$78
1.00 - 1.49$105
1.50 - 1.99$121
2.00 - 2.99$169
3.00 - 3.99$250
4.00 - 4.99$331
5.00 - 5.99$470

Of course, grading is also available for diamonds larger than 5.99 carats whenever needed too.

AGS grading would likely cost $100 to $300 through your local jeweler (they only deal directly with approved jewelers. You can use their site and do a zip code search to help you find local jewelers (which a radius that you set) that are approved to send them diamonds for grading. You would want to call them to confirm that they’re willing to do it for you and to check on what they’re going to cost you. Of course, the total cost includes the actual cost of the lab work, plus whatever markup the jeweler wants to include on the service, so shopping several would probably be a good idea.

How Long Does it Take to Have a Lab Diamond Certified?

Diamond grading typically takes anywhere from 10 to 21 days. If you’re in a hurry, most labs will give you to the opportunity to pay an extra fee to expedite the grading process. Once you confirm the amount of the fee, and how much time the rush status should be able to shave off of your overall anticipated wait time, you can decide if it’s something worth paying for.

Diamonds are measured, studied, and plotted. They’re evaluated with a number of tools, and by a number of different gemologists. By having multiple gemologists evaluate each stone, the final grading assigned is confirmed to be accurate. All of this takes considerable time, which is why the grading process typically takes several weeks instead of several days.

How to Submit Lab Created Diamonds to a Laboratory for Grading

Diamonds can most easily be evaluated, for grading, when they’re loose and unmounted, so most labs require that the diamonds sent for evaluation come to them this way. Some labs will perform very limited testing and provide very limited information on mounted diamonds. For example, to simply find out whether a diamond is lab grown or earth mined, you wouldn’t necessarily need to unmount a diamond from its setting, but to study and report on the qualities and positions of inclusions, they would need it to be loose.

If possible, have a jeweler do a simple sketch of your diamond. They can look at it under magnification and provide a very simple sketch of identifying characteristics. The sketch would show, for example, where inclusions are located in the lab diamond. The size, groupings, and positions of those inclusions can be very unique, and a great way to identify your diamond in the future. Reputable labs are very careful with the diamonds that are sent to them, but if the lab somehow sent back the wrong diamond, the sketched map of your diamond could help you to discover the error.

Make sure your diamond is shipped through a reliable carrier and insured for its full value. The lab you choose for grading should have a site that offers a list of specific instructions to review and follow.

My Recommendation for the BEST Lab-Grown Diamond Grading Lab

Because both GIA and AGS really aren’t viable options in many cases (for reasons outlined above), and because IGI has proven so detailed and dependable in grading lab cultured diamonds, they’re my recommended lab for grading these stones.

Independent sources also validate the wisdom in using IGI. One of the largest insurance underwriters has expressed their trust in IGI gradings. They have millions and millions of dollars on the line, so it’s critical that the gradings they accept are an accurate evaluation of gem characteristics.

Rappaport is a trusted industry watchdog that researched grading laboratories and reported on their findings. They sent diamonds to be tested by multiple labs, and found that IGI grading was extremely strict, and in fact, nearly identical to GIA’s in each instance. In the final ratings, they came in only slightly behind GIA in #2 among all those tested.

In summary of their findings, Rappaport said, “It appears that some labs – such as IGI, which ranks second in the Laboratory Quality Index but fifth in the price ranking – are being punished in their pricing and that their diamonds are selling for less than what their grading standard deserves.” This means that IGI graded diamonds are, in their findings, a great value. Their grading standard is essentially on par with GIA, but IGI graded diamonds sell at a discount compared to your average GIA graded diamond—which means you get to have your cake and eat it too when you buy an IGI graded diamond!

Rappaport isn’t alone. IGI is trusted by countless manufacturers, retailers, and consumers of lab-grown diamonds around the globe.

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