AGTA’s DYNAMIC Seminar with Dr. James Shigley, Dr. Aaron Palke, and Wim Vertriest
GIA’s Team Discusses What it Takes to offer a Country of Origin Report
Three blue sapphires sit on the table. Same color. Same clarity. Same size. Same overall appearance.
At first glance, there may be nothing to separate them.
But ask where they are from, and everything changes.
One may be from Kashmir. Another from Sri Lanka. The third from Madagascar. They may look remarkably similar, yet once the phrase “country of origin” enters the conversation, the trade may — and most certainly will — value them quite differently.
Determining Origin: The Research Behind the Report
On the second day of AGTA’s DYNAMIC Seminar series, Dr. James Shigley, Wim Vertriest, and Dr. Aaron Palke of GIA’s gemological research department, walked us through what actually stands behind a geographic country-of-origin report — how challenging, time consuming fieldwork, large and reliable reference collections, and PhD-level laboratory data converge to support country-of-origin opinions on colored stone reports. What emerged was not one sample, one test, or one instrument, but a complex, integrated system.
Dr. Shigley opened the presentation plainly: “An origin report is an expert opinion based on documenting the properties of the gemstone at the time we examine it.” It was a careful choice of words —”an expert opinion.” Not a guarantee. Not a proclamation. An opinion, grounded in science – of course.
A great deal must happen before GIA puts their name on an emerald, sapphire, or ruby country of origin report.
And if that wasn’t challenging enough, now, making it even more challenging, the list of gemstones eligible for those reports is expanding.
You Can’t Grade Without Master Stones
Shigley made what may have been the most useful analogy of the topic. If you don’t have reference stones of known origin, trying to determine geographic source is like color grading a diamond without master stones.
“If you don’t have reference stones…,” Shigley explained, “and you’re on the D-to-Z scale, then you don’t know where you are.”
The room understood that immediately. Okay, so how good of a master set do you need?
Shigley emphasized that origin work depends on having well-documented comparison materials. You need stones of known provenance, stones collected under controlled circumstances, and stones that can anchor the database.
Without that, the exercise just becomes guesswork. And guesswork is not a service.
Why Geology Complicates Everything
One of the more sobering reminders came when Shigley pointed out something we rarely stop to consider: “Nature doesn’t really respect manmade borders.” And that line would be echoed later by Dr. Palke… but Shigley set the stage first.
Gem deposits can cross geopolitical boundaries. Secondary deposits may lack their original host rock. Some geologic environments produce very similar material in different countries. Conversely, very different environments can exist within the same country.
Why does all of this matter?
Origin reporting assumes that different deposits impart distinct characteristics to a stone. “That is true in some cases,” he said, “but it’s not always true.” That was not said defensively. It was said as geological science.
A Brief Detour: Why Diamonds Are Different
Shigley then addressed a question that inevitably surfaces in every origin discussion: Can you determine the country of origin of a diamond?
His answer was simple. “No.”
“If you hear of an article or a company saying, ‘We solved this problem, we know how to tell where diamonds come from,’ I would be skeptical.”
Why not?
Diamonds form deep in the mantle, not in the crust. They do not carry country-specific crustal signatures. Kimberlite transport to the surface is rapid. Any trace elements present reflect mantle conditions — not mine location. And country of origin relies on crustal geological signatures.
For diamonds, what GIA offers is rough-to-polished matching — tracking a stone from known rough to its cut form. But that is fundamentally different from determining geographic origin.
It was good that Shigley brought this up, as the trade has a habit of blending the two — diamonds and colored gemstones — together.
Research Is the Service
When Wim Vertriest took the microphone, the tone shifted. It became more operational. More structural. He spoke with conviction — and he spoke freely. No filters. Just the way we like it.
“Research is the foundation for all of these things,” he said, referring back to Dr. Shigley’s presentation on country of origin reports. “We don’t just go out and guess these things.”
Research, in this context, is not abstract theory. It is infrastructure.
He described what he called the three pillars of scientific work at GIA: qualified, experienced staff; proper equipment — and knowing how to use it; and reliable samples.
That last point — reliable samples — is often overlooked. “If you collect a bag of gems, all you have is a bag of gems.”
The room understood that immediately. Without documentation — without knowing exactly where a stone came from and under what conditions it was collected — the data attached to it is compromised from the start.
And while instrumentation plays a role, Vertriest was equally clear that equipment alone does not create expertise. “Any idiot with $20,000 can go buy a spectrometer and start printing wiggly lines. That doesn’t mean anything.”
And then, “I would trust any qualified gemologist with a 10× loupe over an idiot with a million dollars’ worth of equipment.” No filters. Blunt, yes?
But the point was precise. Instruments generate data. People interpret it. And interpretation depends on expertise, calibration, experience — and reliable reference material.
From Mine to Database: The A–F System
Vertriest then walked us through GIA’s sample reliability classification — A through F — a system designed to answer a fundamental question: How much can you trust the origin label attached to a stone?
An “A” sample is mined directly by a GIA staff gemologist. A “B” sample is witnessed being mined by a GIA staff gemologist in the mine. A “C” sample is collected at the mine, but not witnessed coming out of the ground. From there, the chain of custody gradually stretches — to local markets, and eventually to international markets.
Vertriest was candid: most GIA samples are not A’s. Logistically, that is simply unrealistic. Fieldwork is time-consuming, expensive, and often geographically challenging. In practice, much of the research collection falls into the middle tiers — D and E samples — stones collected from miners away from the mine site or from local trading markets.
Ideally, every reference stone would be mined directly by a GIA gemologist. “In an ideal situation,” Vertriest said, “all of our samples would be like this.” But building a global origin database does not happen under ideal conditions.
That reality is precisely why the reference system exists. It documents reliability. And reliability, he made clear, is not assumed.
Not everything that comes from the mine is necessarily from the mine. “Things happen.”
So, field labels are not accepted at face value. “We are extremely critical about every sample we collect.” Stones are polished. Examined. Tested. Compared against field notes and existing reference material. Only then are they incorporated into the database.
“Even if you have an army of PhDs in geology,” he said, “and a million dollars’ worth of equipment… if you don’t work on reliable samples, it’s going to be a waste of everyone’s time.”
Then, as if he hadn’t already, he drove the point home. “If you do a study on Nigerian sapphires,” he added, “and you’re not even sure that your sapphires are from Nigeria, what the hell are you even doing?”
When Geology Helps — and When It Doesn’t
Dr. Aaron Palke brought the discussion back into the laboratory. “Geology is key,” he began.
The basic assumption behind origin work, he explained, is that different geologic environments impart different observable and measurable features. “The hope is that the geology was distinct enough… that it imparted distinct properties on those two stones.”
In some classic cases, it works exactly that way. For example, Palke explained that rubies from marble-hosted deposits in Burma may show inclusion features that differ markedly from rubies formed in the volcanic deposits of Thailand or Cambodia.
“If you saw these nice, iridescent, flat platelet silk particles,” he said, describing the Burmese material, a gemologist could reasonably conclude the ruby formed in that marble-hosted environment.
By contrast, volcanic rubies from Thailand or Cambodia may show something quite different: “little melt relics… little ancient blebs of magma that were trapped in these rubies when they were formed in that igneous volcanic environment.” In cases like these, microscopy can be decisive.
But the problem, he explained, is that geology does not always cooperate with political borders. “… sometimes geology fails us.”
Palke showed examples of Sri Lankan and Madagascar sapphires whose inclusion scenes looked strikingly similar. The reason lies far deeper in geological history. Roughly 550 million years ago, those landmasses were joined. The sapphires formed under nearly identical conditions before continental drift separated them. Different countries. Same ancient geology.
“Nature doesn’t really respect manmade borders,” he reminded the audience.
Chemistry, Overlap, and Experience
Palke then turned to trace-element chemistry.
Using LA-ICP-MS analysis, laboratories can measure extremely small concentrations of chemical elements within a stone. Sometimes those chemical signatures separate deposits cleanly.
Sometimes they do not.
“You can see all these spots… overlap on top of each other,” he said, pointing to a plot where samples from different deposits clustered together. When that happens, chemistry alone is not enough. “We have to look for very subtle clues.”
That means combining multiple tools — microscopy, spectroscopy, trace-element chemistry, and comparisons with the reference database.
“We need to look for as many different lines of evidence as possible.” It was not presented as a formula. It was presented as a practice.
Fieldwork Is Never Finished
One of the more compelling moments came in a case study about revisiting an old Thai sapphire deposit that many believed inactive. When GIA collected new samples and added them to the database, previously “unknown” stones in the lab suddenly had a match.
The lesson was subtle but important: origin confidence is not static. Deposits reopen. Production shifts. Reference collections must evolve.
Field gemology, in that sense, is not a one-time expedition. It is maintenance.
Knowing All of That, What Does It Take?
Sitting in the seminar hall, what stood out was not bravado. Again and again, the speakers returned to the same point: origin determination is not simple. It requires fieldwork, large and reliable reference collections, sophisticated laboratory analysis, and experienced interpretation.
And even with all of that, the conclusions remain expert opinions — not guarantees.
The message was clear, even if it was never stated directly: this work is challenging, very expensive, and constantly evolving.
GIA’s country-of-origin reports may appear brief, but the science behind them is anything but.
And after hearing what it takes to produce one, that small “country-of-origin” line on a laboratory report now carries a lot more weight.
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