International Gemmological Institute: How Does This Blackstone-Backed Company Profit From Diamonds?

Synopsis: International Gemmological Institute India makes money by being the trusted referee of the diamond trade. Backed by Blackstone, it profits every time a diamond is verified, not when prices rise. As lab-grown diamonds scale globally, IGI benefits from higher volumes, repeat demand, and strong operating leverage.

Diamonds change hands worth thousands of crores every year, but very few people decide what those stones are actually worth. Behind the glitter sits a quiet, high-margin business that profits every time trust needs to be verified, regardless of whether diamonds come from deep underground or from a laboratory. How does this Blackstone-backed company remain at the centre of this system and continue to make money as the industry itself evolves?

About The Company 

International Gemmological Institute India operates at the centre of the global jewellery certification ecosystem. Backed by Blackstone, the company is India’s largest independent player in diamond and gemstone certification, commanding nearly half of the domestic accreditation market. Its footprint spans 31 laboratories and 18 Schools of Gemology across 10 countries.

Over the past five decades, IGI has built its business around verifying trust in an industry where authenticity is everything. Its services cover certification of natural and lab-grown diamonds, grading and origin reports for coloured stones, and identification and valuation of finished jewellery.

As lab-grown diamonds gain acceptance and scale, IGI’s role has expanded further, with the company screening millions of stones to clearly distinguish between natural and man-made products, reducing ambiguity for both retailers and end consumers.

This ability to standardise quality and disclosure across geographies has helped IGI remain relevant irrespective of where a diamond is bought or sold. Its laboratory reports act as a common reference point, bringing confidence to transactions across the jewellery value chain.

The company’s shares are currently trading around Rs. 311, with a market capitalisation of about Rs. 13,429 crore. .Blackstone holds a 76.55 percent stake in the company, while other global institutional investors in IGI’s shareholder base include the Government of Singapore with 1.32 percent ownership and the Abu Dhabi Investment Authority with a 1.33 percent stake.

Grading and Certification Reports

At the core of IGI’s business is what the industry often calls a “certificate,” though in practice this is a detailed grading report. These reports assess and authenticate loose diamonds, gemstones, and finished jewellery. Even experienced professionals rely on specialised instruments and trained gemologists to determine a stone’s true composition, origin, and quality.

IGI examines every gemstone using advanced detection technologies to establish whether it is naturally mined, laboratory grown, or a simulant, followed by expert analysis to identify any treatments or enhancements. Since stones that look similar can differ sharply in value, these reports play a critical role in pricing and transaction confidence across global markets.

Diamond Screening and Detection

IGI provides high-end screening and detection services that are widely used by both industry professionals and global jewellery brands. Every diamond submitted is tested using state-of-the-art equipment to confirm whether it is natural, lab-grown, or a simulant. For loose diamond parcels, stones identified as natural are sealed in tamper-proof packaging that records key details such as the date of analysis, seal number, test outcome, parcel weight, and customer reference.

This process is standardised across all IGI locations, ensuring consistency and reliability regardless of geography. The same screening protocols apply to both loose diamonds and diamond-set jewellery.

Diamond Sorting Services

For diamond parcels up to 0.25 carat, IGI offers sorting services that combine screening with structured grading. Each stone in a parcel is evaluated to detect lab-grown diamonds or simulants and then grouped based on defined quality ranges. These parcels are returned in sealed bags or in IGI’s professional D-Box packaging, which is designed for presentation.

Information such as colour ranges, clarity bands, and, where requested, cut and finish grades are clearly documented. Additional parameters like fluorescence and measurements can also be provided. By maintaining strict grading standards, IGI enables these sorted parcels to function as reliable trading tools across international markets.

Laser Inscription 

IGI Laserscribe allows diamonds to be permanently marked for easy identification. Using a precise laser, alphanumeric characters, brand marks, or personalised messages can be inscribed onto the diamond’s girdle without affecting its appearance. Most commonly, the IGI report number is inscribed, allowing the stone’s full gemological details to be quickly verified. This service is widely used across the diamond industry as a practical way to link a physical stone to its certification.

Registration and Recovery Services

IGI also offers a registration service that records jewellery details in its database. In cases where jewellery is lost, stolen, or damaged, this registry improves the chances of recovery by providing verifiable ownership and identification records linked to the item.

Jewellery Appraisals

Through its appraisal services, IGI helps retailers and consumers document jewellery for insurance and valuation purposes. These appraisals are customisable for individual stores or brands and include screening to identify natural and lab-grown diamonds.

They provide a detailed description of the jewellery, grading attributes, and information on all gemstones and precious metals, along with a retail replacement value. Such appraisals are accepted by major insurance providers, many of which now require independent third-party documentation for high-value pieces.

Blockchain-Based Digital Diamond Certificates

In partnership with GET-Diamonds and YourProof.id, IGI has introduced a blockchain-backed Digital Diamond Certificate. This is essentially an IGI grading or audit report stored permanently on a blockchain, making it resistant to tampering and loss. Designed for both wholesale and retail use, the digital format allows certificates to be easily accessed, shared, and managed online, supporting use cases such as resale, insurance, and digital listings. Once grading is completed, the certificate is delivered directly to the owner’s digital wallet, creating a long-term, verifiable record of a diamond’s quality, authenticity, and ownership.

In simple terms, IGI is the referee of the diamond world. Whenever someone wants to buy or sell a diamond or a piece of jewellery, IGI checks it very carefully to make sure it is real, to see how good it is, and to confirm whether it came from the earth or was made in a lab. After checking, IGI gives a report that tells everyone exactly what the stone is, so nobody has to guess or worry. This helps buyers and sellers trust each other and makes sure diamonds are traded fairly.

How Much Money Do They Make? 

In Q3 CY25, the number of reports issued rose from 2.7 million in the same quarter last year to 3.5 million, translating into a 26 percent year-on-year increase. EBITDA margins stayed broadly steady at around 58 percent compared with 58.8 percent a year ago, and PAT margins showed only a marginal softening from 43.8 percent to 42.7 percent, highlighting the operating leverage in the business.

On a consolidated basis, lab-grown diamonds have emerged as the single largest revenue driver. In Q3 CY25, certification revenue was split with 52.3 percent coming from lab-grown diamonds, followed by 20.9 percent from natural diamond jewellery and 16.7 percent from natural diamonds. Lab-grown diamond jewellery contributed 8.2 percent, while gemstones and other certification services made up the remaining 1.9 percent. This mix clearly reflects how IGI has benefited from the rapid adoption of lab-grown diamonds across global markets.

In absolute terms, consolidated revenues in Q3 CY25 clearly reflect this shift in the business mix. Certification of lab-grown diamonds generated about Rs. 153.8 crore, making it the single largest contributor by a wide margin. Natural diamond certification contributed Rs. 49 crore, while certification of natural diamond jewellery added Rs. 61.5 crore.

Lab-grown diamond jewellery accounted for Rs. 24.3 crore, and gemstones and other certification services contributed Rs. 5.7 crore. In addition to this, other operating income during the quarter stood at Rs. 9.6 crore.

While volumes have risen, pricing has seen some pressure. The average realised price per report declined to Rs. 854 in Q3 CY25 from Rs. 898 in Q3 CY24, reflecting a 5 percent drop year-on-year. This indicates that growth is being driven more by higher throughput and changing product mix rather than pricing increases.

The longer-term standalone numbers paint an even clearer picture of IGI’s profitability engine. Between CY21 and CY24, the number of reports issued grew at a compound annual growth rate of 29.5 percent, rising from 4.3 million to 9.3 million. Over the same period, EBITDA margins expanded from an already high 66 percent to 72.8 percent, with EBITDA itself growing at a CAGR of 33.5 percent.

Profitability strengthened further at the bottom line, with PAT margins improving from 47 percent in CY21 to 55.9 percent in CY24, and PAT growing at a CAGR of 36.8 percent. Together, these numbers highlight a business that has scaled rapidly while becoming more profitable with size.

At its core, International Gemmological Institute India is not betting on diamonds becoming more expensive. It is betting on one simple idea: whenever a diamond is bought or sold, someone needs to trust what they are getting. As more diamonds enter the system, especially lab-grown ones that look identical to natural stones, that need for verification only increases. This is why IGI continues to grow even when pricing per report softens. Higher volumes, repeat checks, and standardised processes keep the engine running.

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