Interview with GCAL: Grading Reports and 8X Diamond Cuts

GCAL by Sarine is a US-based company that offers a diverse range of services, from diamond grading to precious metal testing, to damage and restoration advisories.  However, their scope of work extends far beyond just evaluating the stones and jewelry submitted to their labs in New York and Surat, India. GCAL aims to drive the diamond industry into the future. President Angelo Palmieri and VP of Product Development and Senior Gemologist Sharrie Woodring spoke with us about how the company is introducing AI technology into their diamond grading process, and elevating the classic diamond grading report. They also described how GCAL is not simply analyzing diamonds, but advancing how they are cut and faceted by creating ultra-precise parameters for a variety of different shapes that mathematically maximize performance. 

How are GCAL's diamond grading reports different from those issued by other labs?

Angelo: We produce a highly visual, data‑rich certificate that lets buyers see exactly what they're purchasing and why it carries value.

When my parents founded GCAL twenty-five years ago, after a year at an online diamond start‑up, they saw early that the internet would reshape retail. From day one, they built our reports around the idea that a picture is worth a thousand words: every technology we add serves the consumer, not merely to impress, but to educate.

Photomicrographs are a great example of what sets GCAL apart. Let's say we're looking at a GIA VS2 diamond and we see a plot with a crystal in the center of the table. OK, so we know there's a crystal under the table. We don't really know the size, the color, the reflections, but if you have a photomicrograph all of a sudden now you know. "Oh, that's a black crystal, I want to stay away." Or, "Oh, that's a transparent crystal, it's small and it doesn't reflect. I'm actually getting great value because maybe it was harshly graded because of location."

Besides offering a better understanding of clarity features, do photomicrographs help buyers become familiar with individual stones in other ways?

Sharrie: With fancy shapes, most shoppers don't immediately grasp the outline—whether it's elongated or wider, where the corners sit, or the exact faceting style. A photomicrograph reveals all of that at a glance.

It seems like the additional details in your reports removes a lot of ambiguity and makes it much harder for someone to do something nefarious like associate a stone with a report that was created for a different gem.

Angelo: Exactly. Beyond laser inscription, precise measurements, and Gemprint, which all come standard, our premium reports add high‑resolution photos and 360° video, eliminating any doubt about matching a stone to its certificate.

The measurements that you take when developing a grading report are so small and precise that they have to be done with the help of a machine. Can you explain what technology you use?

Sharrie: First, we weigh the diamonds, then we capture their unique Gemprint for identification. For measuring, one of the instruments we use is Sarine HD, which allows us to take extremely detailed and accurate measurements. This advanced technology uses high-definition imaging to capture the stone's dimensions and proportions, down to minute fractions of a millimeter.

With all of this specialized technology, what is the current role of a human grader in the GCAL lab?

Sharrie: Every diamond still passes human eyes. We use a consensus system: either two graders plus a third if they disagree, or the AI system followed by two graders. Some shapes and lower‑color stones aren't yet AI‑supported, but wherever possible the machine provides the first opinion.

Angelo: All GCAL graders hold GIA Graduate Gemologist credentials, but that's only the starting point. We may interview ten qualified applicants to hire one, and every new gemologist must pass a rigorous hands‑on proficiency test.

Do you now use AI as part of your standard evaluation for all eligible diamonds?

Sharrie: AI has become a part of our grading process. 

Angelo: The machine grades first, then senior graders review the result blind. That combines the speed and precision of AI with human judgment that can catch rare anomalies. We're introducing the technology gradually so the personal element isn't lost.

We understand that technology is the future, but we're committed to blending it thoughtfully with human expertise as every diamond moves through the lab.

How long did it take to develop your AI and when did you start using it in the lab?

Angelo: We've used Sarine's AI platform for two years. Sarine launched the hardware‑and‑data foundation about seven years ago; our role has been to refine it to GCAL's standard.

Initially, we operated solely in New York, but clients needed an overseas option. Rather than replicate the multi‑lab inconsistencies we've seen elsewhere, we partnered with Sarine so our machines abroad match New York's benchmark.

That collaboration proved itself in New York for more than a year before we opened our Surat facility, ensuring seamless alignment.

How did GCAL begin integrating the AI with your grading team?

Angelo: We started in the lab in New York because we wanted to ensure that it was aligned with our grading. We didn't open our second location in Surat, India, until well over a year into the partnership. So we had a lot of experience with it before it became a part of our process overseas.
But again, remember that there's no stone that gets graded by machine only and goes out. Everything in the GCAL lab is done both by machine and by people.

The Sarine AI Color grading instrument features a daylight-equivalent lighting environment, replicating the conditions used by gemologists. Instead of relying on the human eye, high-resolution lenses capture the diamond's color from every angle. Photo courtesy of Sharrie Woodring.

You proudly advertise that yours is the only gemological laboratory that guarantees their quality grades. Can you explain that process and how you resolve questions about any of your grading results?

Angelo: This has been a hallmark of GCAL since its inception. The reason my parents founded this lab was because they were sick and tired of all the games the grading labs played. Their mission was to show the industry that you could operate a diamond grading lab with integrity and stay in business. 

Up until the point when GCAL entered the market, you basically had GIA and non-GIA labs, and the non-GIAs carved their niche by over-grading, over-appraising, and inflating things. That is what many of them were known for. 

We have a 4C's zero tolerance guarantee, meaning that if we grade a stone an E color and it's determined to be an F color, we pay the consumer the difference in retail dollar amount. In some cases, our liability is tens of thousands of dollars for a potential grade or two, and over the past twenty-five years, we've paid a few legitimate claims, satisfying our grading guarantees.

Here is an example. An appraiser looked at a stone post purchase, flagged it, and said "I don't think this is an SI2. I think it's an I1." We have a blind process where the stone is resubmitted to our lab. In this case, the stone was determined to be an I1, and I think we paid $2000, which was the difference in price between an SI2 and I1 diamond. 

The Sarine Clarity AI grading instrument captures a series of finely focused images as it steps through the diamond from table to culet. Using high-resolution imaging, the AI-powered system maps internal inclusions and blemishes, automating and standardizing the grading process to provide consistent, objective clarity grades. Photo courtesy of Sharrie Woodring.

Sharrie: And that's something you just don't see elsewhere. You will see on reports from other labs that there are a lot of disclaimers in fine print (about grading tolerances). That's their legal out. But at GCAL, we believe in standing behind our work. If we put our name on a grading report, it means something. That's why people trust us.

Would you also trust any of the GIA labs with re-grading your diamonds and accepting the results without question?

Angelo: In principle, I would welcome relying on a single external lab; unfortunately, practical experience shows we cannot. Even when GIA operated only two facilities—New York and Carlsbad, prior to its 2008 expansion—we already saw significant grading discrepancies. Today, with nine labs across eight countries, those inconsistencies have only increased. If we let such variable results arbitrate our own grades, we would jeopardize the consistency that underpins our guarantee.

At GCAL, we financially stand behind every report we issue. Because GIA does not assume comparable responsibility for the accuracy of its grades, let alone ours, we cannot allow them to determine the validity of our guarantee.

Every GCAL team member understands that our reputation and financial exposure hinge on each diamond we certify. That level of accountability is not embedded in GIA's structure, and it is precisely why we handle any re-grading internally.

Looking to the future, do you think labs with lesser accuracy and consistency will survive?

Angelo: When you think about the US, you primarily have 4 labs remaining….GCAL, GIA, IGI, and GSI, and overseas, HRD still exist.  

IGI, through some publicly disclosed and highly questionable methods, has now really gained massive market share. They have quadrupled their revenue in the last five years, and they're climbing the ranks, are a public company, and I think they have longevity.

Can you explain what you mean by "questionable" and how GCAL is different?

Angelo: IGI's rapid expansion stems partly from 'in‑factory' grading units disclosed in its IPO prospectus. Factories purchase the equipment and supply most staff, meaning the same organization that produces the stones participates in grading them. That raises reasonable questions about independence and consistency, concerns retailers will ultimately have to weigh.

To conclude our discussion about diamond grading and the progress that GCAL is making in that area, where do the gemologists working for small jewelry businesses and appraisers fit in? At this point in time, to properly grade a stone, it seems like you need a lot of cost-prohibitive equipment because what your technology is measuring is beyond human capability.

Sharrie: Appraisers do so much more than just grade diamonds. They hardly ever see loose stones - most of the time, the diamonds are already set and come with a grading report. Of course, it's still important to check the report and make sure everything looks accurate. But an appraiser's job is way more involved. They have to identify every stone in a piece, look at the metal, evaluate colored gems, assign a value, and even consider the age and condition. It's really about understanding the whole piece, not just the diamond.

Sarine isn't yet producing the instruments for appraisers or independent gemologists to buy. They're laboratory equipment. They're expensive, big machines. They aren't the type of machines that an appraiser is going to buy at this point. That's not the objective. 

Angelo: When a mounted diamond comes into our lab, we're so much more limited in what we can do. Do I see the potential of Sarine creating desktop, portable color and clarity grading systems for loose diamonds? Yeah, I think that is in the future. But, one that is going to handle mounted diamonds? That is more complex and I don't see that in the immediate future.  

I think the single most important thing is for an appraiser is to be able to definitively determine natural, lab grown, and knowing when you're unsure.

At this point, are you confident that GCAL by Sarine technology can identify all lab-grown diamonds submitted to the lab?

Sharrie: Yes. There are several telltale signs that we're looking for. It's a whole combination of the factors. For example, we're looking for the N3 center - nitrogen-related defect common in natural diamonds but very rare in lab-grown diamonds, and we're looking at the growth structure, and we're looking for the birefringence patterns. So it's a whole broad range of characteristics we're analyzing to make a determination. 

Do I think that it could be possible down the road? It could be. But we're not there yet and detection technologies continue to advance. For now, most lab-grown diamonds are being sold transparently, and there's no widespread effort to intentionally disguise them as natural.

The Next Generation of Diamond Cut Parameters

Let's move on to the 8X cuts that GCAL has developed. Angelo, you have said that "Cut is the most controllable of the 4C's." But, it is also the C that is perhaps the least well understood by the general public. How are your 8X stones different from other diamonds?

Angelo: We started with rounds. The science of rounds is pretty well established. We felt like the Triple X cut (cut, polish, and symmetry), it's a very generous and forgiving standard. When it came out twenty years ago, it wasn't easy. But cutting overall has really improved, and cut evaluation needed an update because pretty much everything was hitting this Triple X mark. 

If somebody walks into the store, wants the best color, great, you give them a D. Somebody wants the best clarity, great, you give them flawless. If somebody wants the best cut, what are you giving them? And I don't think there was really an answer. We believe 8X is the answer. When somebody wants the best cut, you give them an 8X. There was a void in the market for trying to find basically a perfectly cut diamond. People were looking for this type of hearts and arrows, a perfectly cut diamond that was accurately graded. It didn't exist. 

Sharrie: We would get in several to look at, and then none of them would be what they were stated to be. Even if it's a Triple X. In the lab, we see so many stones, and we see stones that are just stunning, and we think, "wow, look at that stone!" But if we were to try to find a stone like that by looking at listings, it would be incredibly hard to find that stunning stone.

Angelo: So we really looked at 8X as a refinement and a true elevation of the existing cut grades out there. We structured it to be very stringent. Yes, tech-heavy in terms of the performance, but that's to make sure we have a consistent and accurate assessment across all stones submitted. 

When you get into fancy shapes, we recognize that there are a lot of different length-to-width ratios and shape outlines. Sharrie mentioned earlier in the interview that some people like the chubby oval while others like the elongated oval. The same goes for marquise. The difference is a ratio of 1:1.80 or 1:2.10. But on an oval, for example, we actually have tolerances and measurements that go from a 1.35 l/w ratio to a 1.55. On a marquise, we are 1.75-2.20. So we're allowing for personal taste, but we have different proportion sets at the different length to width ratios that hit on the different performance metrics we want.

There is no deviation on a princess cut or round. For princesses, normal variation is 1:1.05. We restrict it to 1:1.015, so we want it really square. 

The GIA has recently written an article on elongated fancy shape cut assessments, where they have identified millions of combinations of different angles and measurements, and facet types. And they're right in the math. But I think one of the shortcomings of the Triple X is that it actually doesn't measure light performance. They're projecting that based on the physical characteristics that they assess. 

Sitting here in 2025, we have all the tools and technology to actually measure it. So, instead of trying to come up with the millions of combinations that might make this diamond sparkly, we physically measure it. And so it allows us to have a more simplified approach, which is - here are the constraints, outside of these constraints, stones don't perform well. But within these proportion sets, these physical characteristics, angles, and measurements, this is where we see the highest performance of each of these shapes. Now you're measuring direct assessment of optical brilliance, direct assessment of fire, direct assessment of simulation, direct assessment of optical symmetry, and direct assessment of shape aesthetics. Within the constraints, our system is flexible in terms of personal taste, but stringent across the performance metrics.

How do you report a cut grade on your certificates? Do you use the traditional terminology of Excellent, Very Good, Good, Fair, and Poor?

Great question. So, it's eight categories we assess, each of which has to be excellent to give you the 8X.

There's polish, which is rated up to excellent. That's using the standard scale. We have external symmetry, again rated up to excellent on the standard scale. Then we have fire, brilliance scintillation, optical symmetry - those have to be excellent. Shape aesthetics is really more of a pass/fail type of thing with length to width ratio, minimal bow tie, no chips, and so forth. On the proportion side, we have very, very strict proportions and combinations depending on the length-to-width ratio.

Who manufactures 8X cut diamonds?

We don't buy, sell, or cut 8X diamonds ourselves. Instead, we guide manufacturers who want to achieve 8X.

Here's how the process works:

Pre-screening: Manufacturers send us their Sarine HD DiaMension scans. Using ray-tracing and optical-symmetry software, we model fire, brilliance, and symmetry to identify stones, likely or unlikely, to make 8X. This service is complimentary; it spares clients the cost and duty of shipping stones from India to New York unless they have a realistic chance of success.

Conditional feedback: Our digital review can't reveal issues like chips, polish defects, or haze, so any approval is conditional on the physical inspection. If a stone clearly won't qualify, we advise the client not to export it.

Final certification: Only diamonds shipped to our New York lab undergo the full 8X evaluation. By pre-screening every file, we help manufacturers maximize their pass rate and avoid unnecessary logistics costs.

Previewing all of those scans must be a huge undertaking for your staff.

We dedicate staff specifically to reviewing incoming scan files. Because of the time‑zone offset, we often receive a batch overnight and return feedback the same business day.

We view this support as part of our responsibility for setting a demanding standard.

Is the weight retention of an 8X cut diamond similar to other cuts, or is it higher?

Sharrie: That's very good insight. It's expensive to cut such high-precision stones, and it isn't for everybody because it does cost more. There is weight loss to get to this level of precision. 

With so much extra weight loss, are many people cutting natural diamonds to 8X or is it mostly synthetic diamonds where weight loss doesn't really matter?

Angelo: It was created for naturals, but we have certified lab-growns by the thousands. Naturals are basically cut to order. 

How many shapes currently have an established 8X cut?

Angelo: We launched 8X cuts for rounds first. Then princess and oval, followed by pear and marquise. Cushion and radiant cuts are next up. We are very excited about those!