--- title: "Record-Setting Lab-Grown Diamonds: Sizes and What Buyers Can Learn" byline: "Love & Carat" series: education published: 2026-09-30T13:29:30.337Z updated: 2026-09-30T13:29:30.337Z canonical: https://loveandcaratnewyork.com/blog/largest-lab-grown-diamond-records disclosure: editorial sources: - "GIA Examines 34.59 Carat CVD Laboratory-Grown Diamond - https://www.gia.edu/gia-news-press/gia-examines-34.59-carat-cvd-laboratory-grown-diamond" - "IGI certifies world’s largest Lab Grown Diamond: 30 carats - IGI - https://www.igi.org/igi-certifies-worlds-largest-lab-grown-diamond-30-carats/" - "IGI Certifies Historic 50.25 carat Lab Grown Diamond - IGI - https://www.igi.org/igi-certifies-historic-50-25-carat-lab-grown-diamond/" - "IGI Certifies Largest Lab Grown Diamond to Date: 35.00 carats - IGI - https://www.igi.org/igi-certifies-largest-lab-grown-diamond-to-date-35-00-carats/" - "GIA Sees Largest CVD Lab-Grown: 34.59 Carats - JCK - https://www.jckonline.com/editorial-article/gia-largest-cvd-lab-grown-34-59/" --- # Record-Setting Lab-Grown Diamonds: Sizes and What Buyers Can Learn _Written by Love & Carat about the stones we sell. Not an independent review._ **The short answer** - In 2023, IGI announced a 50.25-carat emerald-cut lab-grown diamond graded G color and VS2 clarity, days after it graded a 35.00-carat stone on May 29, 2023. - On May 4, 2023, GIA reported that the largest CVD lab-grown diamond it had seen was a 34.59-carat emerald cut graded G color and VS2 clarity. - The records show how fast growth has advanced: IGI's 30.18-carat stone, announced June 9, 2022, was the first polished lab-grown diamond over 30 carats. - For a ring, a record stone is a curiosity; a well-cut, certified stone of wearable size is where your money works hardest. In 2023, IGI announced that it had graded a 50.25-carat emerald-cut lab-grown diamond, days after grading a 35.00-carat record holder on May 29, 2023. On May 4, 2023, GIA reported that the largest chemical vapor deposition (CVD) lab-grown diamond it had seen weighed 34.59 carats. These are feats of engineering, not typical ring stones. They are worth understanding all the same, because they show where the technology is heading. ## Which lab-grown diamonds set size records in 2022 and 2023? Records in this field fall quickly, so every claim below comes with its date. Some stories call these stones "lab-created"; the term means the same as lab-grown. In May 2022, IGI graded a 27.27-carat and a 20.24-carat stone, both record-setting at the time. [JCK reported](https://www.jckonline.com/editorial-article/gia-largest-cvd-lab-grown-34-59/) that both were cut from a 150-carat piece of HPHT-grown rough that IGI examined in February 2022, along with a 15.16-carat pear. Then on June 9, 2022, IGI announced the 30.18-carat "Pride of India", [the first polished lab-grown diamond to exceed 30 carats](https://www.igi.org/igi-certifies-worlds-largest-lab-grown-diamond-30-carats/). The announced milestones from 2022 and 2023 show the progression: | Announced | Weight | Shape and grades | Laboratory | |---|---|---|---| | June 9, 2022 | 30.18 ct | Emerald cut, H color, VS2, CVD | IGI | | May 4, 2023 | 34.59 ct | Emerald cut, G color, VS2, CVD | GIA | | May 29, 2023 | 35.00 ct | Emerald cut, CVD | IGI | | 2023, days later | 50.25 ct | Emerald cut, G color, VS2, CVD | IGI | The two laboratories framed their claims differently. GIA described its 34.59-carat stone as [the largest CVD-grown stone the Institute had seen](https://www.gia.edu/gia-news-press/gia-examines-34.59-carat-cvd-laboratory-grown-diamond), up 111% from a then-record 16.41 carats in 2022. IGI called its [35.00-carat stone "the largest to date"](https://www.igi.org/igi-certifies-largest-lab-grown-diamond-to-date-35-00-carats/). Soon after, IGI described its [50.25-carat stone as the first to pass the "half-century" mark](https://www.igi.org/igi-certifies-historic-50-25-carat-lab-grown-diamond/). Something larger may have been graded since. For more recent announced milestones, check the press pages of IGI and GIA directly. ## Reading a record stone's grades The reports described here use familiar terms such as carat, color and clarity, making them useful examples for reading a report. That makes the records a useful lesson in reading a report. - **Carat is weight, not size.** IGI's 50.25-carat stone measures 22.95 × 18.45 × 11.57 mm. GIA's 34.59-carat stone measures 24.94 × 13.95 × 9.39 mm, so it is actually *longer*. The heavier stone is wider and much deeper. Our [carat glossary](/education/carat) explains why millimeters tell you more about how a stone looks on the hand. - **Color.** Three of the stones listed were graded G or H. Both grades sit in the near-colorless range, which is where we'd steer most buyers anyway. - **Clarity.** IGI reported VS2 clarity for the 30.18- and 50.25-carat stones, and GIA reported VS2 for the 34.59-carat stone; IGI's supplied announcement does not give a clarity grade for the 35.00-carat stone. GIA noted [small black graphite inclusions and weak "oily" or wavy graining](https://www.gia.edu/gia-news-press/gia-examines-34.59-carat-cvd-laboratory-grown-diamond) in its stone; it says that kind of graining is sometimes seen in CVD lab-grown diamonds. Our [clarity glossary](/education/clarity) covers what VS2 means in practice. - **Cut.** IGI graded the 50.25-carat stone Excellent for cut, polish and symmetry. - **Type IIa.** This notes that the stone contains very little nitrogen. It is a scientific classification, not a quality grade. All four stones in the table are emerald cuts. An emerald cut's broad facets also make its clarity especially worth checking by eye. But the long, open facets of an emerald cut show inclusions more readily than a brilliant cut does. ## What record sizes say about the technology The announcements show increasingly large polished CVD lab-grown diamonds, alongside an earlier example of exceptionally large HPHT-grown rough. JCK noted in May 2023 that, [generally, the HPHT method has produced bigger stones than CVD](https://www.jckonline.com/editorial-article/gia-largest-cvd-lab-grown-34-59/). JCK reported that IGI had examined a 150-carat piece of HPHT-grown rough in February 2022, though rough and polished weights are not directly comparable. In May 2023, IGI announced record-setting polished CVD lab-grown diamonds of 35.00 and then 50.25 carats. **Record lab-grown stones reported in May 2023** | Record lab-grown stones reported in May 2023 | carats | | --- | ---: | | CVD emerald cut, GIA 2023 | 34.59 | | HPHT marquise, from one rough | 27.27 | | HPHT emerald cut, from one rough | 20.24 | | CVD, GIA's 2022 record | 16.41 | | HPHT pear, from one rough | 15.16 | Source: GIA Sees Largest CVD Lab-Grown: 34.59 Carats - JCK, 2023-05-05. Growth times hint at how far the process has been pushed. IGI said the rough for the 30.18-carat stone [took approximately four weeks to grow](https://www.igi.org/igi-certifies-worlds-largest-lab-grown-diamond-30-carats/). The crystal behind the 50.25-carat stone [was grown over eight months](https://www.igi.org/igi-certifies-historic-50-25-carat-lab-grown-diamond/). IGI's eight-month growth figure gives a sense of the work behind that stone, without telling us how the growth was managed. Post-growth treatment is part of the story too. JCK reported that GIA's 34.59-carat stone [was also annealed with HPHT treatment](https://www.jckonline.com/editorial-article/gia-largest-cvd-lab-grown-34-59/) after growth. Our guide to [CVD vs HPHT lab-grown diamonds](/blog/types-of-lab-grown-diamonds-cvd-vs-hpht) explains how the two methods differ and why a stone can involve both. > This more than two-fold increase in size within one year is an impressive technical achievement in CVD diamond growth > (GIA Examines 34.59 Carat CVD Laboratory-Grown Diamond) ## Why grading matters more as stones get bigger When GIA announced its record, it paired the technical praise with a warning. The same statement said that [correct identification and disclosure are critical to maintaining consumer trust](https://www.gia.edu/gia-news-press/gia-examines-34.59-carat-cvd-laboratory-grown-diamond). IGI made a similar point when it announced the 35.00-carat stone, [stressing screening, grading and disclosure](https://www.igi.org/igi-certifies-largest-lab-grown-diamond-to-date-35-00-carats/). For a buyer, the lesson is simple. An independent grading report helps you check what a diamond is, especially when you are comparing unusually large stones. Every diamond we sell comes with a GIA or IGI grading report. Our [certificate glossary](/education/certificate) shows how to read one line by line. **Check the report yourself:** GIA lists a Report Check service on its website; ask IGI directly how to verify an IGI report. Before paying, compare the weight, measurements and grades with the report you received. ## What a buyer can realistically find The record stones in these announcements are exceptional examples, not a guide to ordinary shopping. IGI's announcements described them going on display at a trade show in Las Vegas. IGI reported that the 50.25-carat stone had already been sold when it announced plans to display it. You do not need a record-setting weight to choose a large lab-grown diamond. Several points hold whatever size you're considering: - **Compare size and price together.** Compare prices for certified stones with similar grades rather than assuming the heavier stone is the better choice. We don't list prices in this guide; compare certified stones side by side instead. - **Lab-grown diamonds usually cost less than comparable natural ones.** For a larger stone, comparing the cost of a lab-grown diamond with a comparable natural diamond can be especially worthwhile. - **A large stone is not an investment.** Diamonds are not investments, and nobody can promise what one will resell for. If you insure a large stone, your insurer may ask for an independent appraisal. - **Clarity starts to matter more.** In a smaller brilliant cut, a VS2 inclusion may be hard to see without magnification. On a big emerald cut it has more room to show, so look for a stone that is [eye-clean](/education/eye-clean), not just one with a good letter grade. **Think in millimeters:** Two stones of similar weight can look quite different in size. Compare the length and width on the report, and picture them on the hand, before you pay extra for a higher carat figure. ## The sensible way to spend on a large stone The reported grades offer a useful reminder: IGI and GIA reported G or H color and VS2 clarity for three of these unusually large stones. You don't need D color or flawless clarity for a stone to look superb, though it's worth checking inclusions carefully at a larger size. If you want a large center stone, here is where we'd put the money: 1. **Cut first.** Good proportions can affect brightness; compare how the stones actually look, not just their carat weights. 2. **Near-colorless color.** G or H faces up white in most settings, and even warmer grades can look lovely in yellow gold. 3. **Eye-clean clarity.** Pay for clarity only up to the point where you stop seeing inclusions. Be stricter with emerald and Asscher cuts than with ovals or rounds. 4. **Size last.** Spend what's left on size, measured in millimeters, not on the carat number alone. **A record stone proves what growers can do; a well-cut, certified stone of the size you'll actually wear is where your money works hardest.** When you're ready to compare, browse our [center stones for engagement rings](/). Choose by the report, look at the millimeters, and remember that the cheaper stone is often the right one when it looks the same. ## Frequently asked questions **How much is a 20 carat lab-grown diamond?** There's no single price for a 20-carat lab-grown diamond; compare the grades and prices of available certified stones individually. Compare certified stones report by report, and remember that lab-grown diamonds usually cost less than comparable natural ones. **Is a very large lab-grown diamond a good investment?** No. Diamonds are not investments, lab-grown or natural, and nobody can promise what a stone will resell for. Buy a large stone because you love wearing it. **Is there a limit to how big a lab-grown diamond can be?** These sources do not establish an absolute maximum size. For more recent announced records, check IGI's and GIA's press pages. **How much should you spend on an engagement ring if you make $100,000 a year?** We don't give financial advice, and there's no rule you have to follow. Settle on a figure you're comfortable with, then let a jeweler show you where the eye stops seeing a difference so every dollar counts.