IGI Certification History: How IGI Became the Leader in Lab Grown Diamond Grading

Ouros Jewels

A Three-Person Lab That Became a Global Standard

In 1975, the International Gemological Institute opened its doors in Antwerp — then, as now, the world’s most important diamond-trading city — with a staff of exactly three people. The goal was straightforward: provide independent, third-party grading for diamonds and gemstones at a time when standardized certification was still rare. What followed over the next five decades is one of the more unlikely stories in fine jewelry: a small Belgian lab growing into the largest independent gemological laboratory in the world by volume of reports issued.

Today, IGI operates 31 laboratories across 10 countries, with grading facilities in Antwerp, Mumbai, Surat, New York, Bangkok, Tokyo, Dubai, Hong Kong, Los Angeles, and beyond. It employs hundreds of graduate gemologists and issues millions of reports annually. That scale is not incidental — it reflects how deeply IGI has embedded itself into the global diamond supply chain, particularly at the manufacturing and wholesale levels where speed and consistency matter as much as precision.

But the chapter of IGI’s history that matters most to modern buyers isn’t the 1975 founding. It’s what happened in 2005.

2005: The Year IGI Pioneered Lab Grown Diamond Grading

When lab-grown diamonds first began appearing in commercial quantities in the early 2000s, the gemological community faced a genuine question: how should these stones be assessed? They are physically, chemically, and optically identical to mined diamonds. They form by two distinct processes — High Pressure High Temperature (HPHT) or Chemical Vapor Deposition (CVD) — but the resulting crystal is the same material. Treating them as a separate category with different grading standards risked confusing consumers. Treating them as identical to natural diamonds without any disclosure risked deceiving them.

IGI’s answer, in 2005, was to pioneer full grading of lab grown diamonds, establishing what would become the industry’s first framework for disclosure, standardization, and authenticity in this category. The approach mirrored what had worked in the cultured pearl market: apply the existing 4Cs — cut, color, clarity, and carat weight — consistently, while clearly identifying origin on every report. A lab grown diamond report from IGI explicitly states “Laboratory-Grown” or “Man-Made,” so there is no ambiguity about what the buyer is purchasing.

This was not a small decision. At the time, lab grown diamonds represented a fraction of the market, and grading them required developing new testing protocols. IGI’s screening process uses spectroscopy and advanced equipment to distinguish naturally mined stones from laboratory-grown ones and from simulants like moissanite. Every stone goes through multiple independent graders — no collaboration between graders until sufficient agreeing opinions are reached — and color is assessed in a standardized viewing environment with the diamond placed upside down, viewed through the side, to eliminate bias.

GIA, the Gemological Institute of America, did not begin issuing reports for lab grown diamonds until 2007 — two years after IGI. That two-year head start, combined with IGI’s manufacturing-level integration, is largely why IGI came to dominate lab grown diamond certification volume. By the time the lab grown market accelerated in the late 2010s and into the 2020s, IGI already had the infrastructure, the protocols, and the institutional knowledge that competitors were still building.

What an IGI Lab Grown Diamond Report Actually Contains

A common question from buyers is whether an IGI certificate for a lab grown diamond is meaningfully different from one for a natural stone. The answer is: mostly no, with a few additions specific to lab grown diamonds.

The core of every IGI report covers the standard 4Cs grading: carat weight (measured with calibrated instruments), color (graded on the D-to-Z scale), clarity (assessed at 10x magnification on a twelve-grade scale from Flawless to I3), and cut (for round brilliants, this includes proportions, symmetry, polish, and an overall cut grade benchmarked against IGI’s brightness and scintillation studies). Fancy shapes receive a four-step assessment combining finish grades with shape-specific proportion requirements.

For lab grown diamonds specifically, the report notes the growth method — HPHT or CVD — and any post-growth treatments. This matters because some lab grown diamonds undergo treatments to improve color after the growth process, and IGI discloses these in the comments section. The report also includes a unique report number that is typically laser-inscribed on the diamond’s girdle, visible only under 10x magnification. That inscription links the physical stone to its certificate, allowing buyers to verify the match via IGI’s online database using the report number or a QR code on the certificate itself.

IGI also holds the distinction of being the world’s first gemological laboratory to receive ISO accreditation in both natural and lab grown diamonds — a technical credential that validates the laboratory’s measurement systems and procedural consistency against international standards. That accreditation covers facilities in the United States, Canada, India, and the United Arab Emirates.

IGI’s Standing in 2026: Scale, Ownership, and the Lab Grown Market

In May 2023, private equity firm Blackstone acquired IGI for approximately $570 million — the largest single transaction in the gemological laboratory sector on record. The acquisition covered IGI’s global operations across India, Belgium, the Netherlands, and other markets. Shortly after, IGI’s Indian operations went public on the National Stock Exchange of India and the Bombay Stock Exchange, making IGI the only gemological laboratory in the world listed on a stock exchange — a level of financial transparency unusual in the certification industry.

The Blackstone acquisition was a clear signal of where the lab grown diamond market is heading. IGI’s India operations generate the majority of its revenue and profit, reflecting the country’s position as the world’s largest diamond cutting and polishing hub. As lab grown diamond production has scaled — particularly CVD production in India — IGI’s certification volumes have followed.

So is IGI certification trustworthy for lab grown diamonds? The honest answer is yes, with some context. For lab grown diamonds specifically, IGI’s long head start, dedicated protocols, and sheer volume of stones processed have made it the de facto standard. The grading methodology applies the same 4Cs framework used for natural diamonds, with the same D-to-Z color scale and FL-to-I3 clarity scale. Multiple independent graders assess each stone. The origin is clearly disclosed. Reports are verifiable online. And IGI’s ISO accreditation provides external validation of its technical processes.

For natural diamonds, some dealers and independent analysts have historically noted that IGI’s grading can trend slightly more lenient than GIA’s — a perception that is more relevant when buying high-value mined stones where a one-grade difference in color or clarity has significant price implications. For lab grown diamonds, where the price differential between grades is smaller and IGI’s expertise is deeper, this concern carries less practical weight for most buyers.

IGI also holds membership with the Responsible Jewellery Council (RJC), reflecting commitments to ethical sourcing and sustainability — criteria that matter to the growing share of buyers choosing lab grown diamonds precisely because of their conflict-free, lower-impact origins.

Why IGI Certification Matters When You’re Buying Lab Grown Diamond Jewelry

Certification is not a formality. Without an independent grading report, a diamond’s stated quality — its color, clarity, cut — rests entirely on the seller’s word. An IGI certificate separates the stone’s characteristics from the seller’s commercial interest, giving buyers a documented, verifiable description they can rely on for insurance, resale, and simple peace of mind.

For anyone shopping for [lab grown diamond engagement rings](https://www.ourosjewels.com/collections/engagement-rings) or certified loose lab diamonds, IGI certification provides a consistent benchmark: you know exactly what grade you’re getting, you can verify the report number online, and the laser inscription on the girdle ties the physical stone to its paperwork. That traceability matters whether you’re buying a 0.5 carat accent stone or a 3 carat center diamond.

At Ouros Jewels, every piece in the collection is built around IGI-certified lab grown diamonds — a deliberate choice that reflects the brand’s commitment to transparency. When a buyer can pull up the report number and confirm the stone’s 4Cs independently, the transaction becomes something closer to a factual exchange than a leap of faith. That’s what certification, done well, is supposed to accomplish.

Fifty-one years after three gemologists set up a grading desk in Antwerp, IGI’s position as the dominant certifier of lab grown diamonds is the result of an early bet on a category that the rest of the industry was still watching from a distance. In 2026, with lab grown diamonds now representing a substantial share of the US engagement ring market, that early move looks less like a gamble and more like foresight.

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