The One Thing Everyone Gets Wrong About Lab-Grown Diamonds: Understanding GIA’s New Certification
Laboratory-grown diamonds are often accompanied by questions around certification and grading, particularly as gemological practices continue to evolve. With one of the world’s most respected authorities, the Gemological Institute of America (GIA), recently updating their approach to assessing lab-grown stones, we want to guide you through this new reporting system, explain what you can expect to see on your certification, and what this all means for your heirloom piece.
Please note that at TMC Fine Jewellers, the most of our precious gemstones are certified by t he International Gemological Institute (IGI). The following information is not applicable for gemstone certified by IGI, as they continue to grade laboratory-grown diamonds using the same, familiar 4Cs framework as their mined counterparts: carat, colour, clarity and cut.
What Is a Laboratory-Grown Diamond?
A laboratory-grown diamond is chemically, physically and optically identical to a mined diamond. They are, quite simply, real diamonds. The only difference lies in their origin. Rather than forming beneath the earth’s surface over billions of years, lab-grown diamonds are created above ground using advanced technology that replicates the natural diamond-growing process. This method allows for a more sustainable and traceable approach to diamond creation, without compromising on quality or authenticity.
Are Lab-Grown and Natural Diamonds Graded the Same?
The short answer is that it depends on the certifying body.
At TMC Fine Jewellers, we choose to work with only the most superb IGI and GIA lab-grown diamonds, that deliver on our commitment of quality, ethicality and attainability. We pride ourselves on transparency and empowering you with accurate education to choose the right diamonds. Here’s how each certifying body certifies these precious gemstones:
The International Gemological Institute (IGI) continues to grade laboratory-grown diamonds using the same 4Cs framework as their mined counterparts: carat, colour, clarity and cut. This is a familiar and detailed grading structure, allowing for direct comparison and transparency. We work exclusively with IGI certified diamonds that fall within D - F colour, VS2 - VVS1+ clarity, and Excellent cut, polish and symmetry. Learn more.
The Gemological Institute of America (GIA), however, has recently updated its grading for laboratory-grown diamonds. While GIA remains one of the world’s most respected authorities in gemmology, it now grades lab-grown diamonds using a framework tailored to their unique characteristics, rather than the traditional 4Cs framework used for natural stones. Under this framework, lab grown diamonds are now classified as either Premium or Standard. Any laboratory-grown diamond that does not meet the minimum criteria for ‘Standard’ does not receive a GIA assessment at all.
As GIA explains, "using descriptive terms for the quality of laboratory-grown diamonds is appropriate as most fall into a very narrow range of color and clarity,” said Pritesh Patel, GIA president and CEO. “Because of that, GIA will no longer use the nomenclature created for natural diamonds to describe what is a manufactured product.”
Every lab grown diamond we select falls within the Premium classification. Our strict parameters and hand selection process ensure we continue to meet the highest quality standards.
Understanding GIA’s ‘Premium’ and ‘Standard’ Classifications
Under GIA’s updated framework, a laboratory-grown diamond classified as ‘Premium’ must meet the highest quality benchmarks. These include very, very slightly included clarity or higher, D colour, excellent polish and symmetry, and an excellent cut grade for round brilliant diamonds.
Diamonds classified as ‘Standard’ meet a combination of premium-level attributes alongside minimum criteria, such as very slightly included clarity, E to J colour, very good polish and symmetry, and very good cut for round brilliant stones. This system reflects GIA’s view that most laboratory-grown diamonds cluster within a narrow quality range, making broad descriptive categories more appropriate than traditional grading scales.
Why Certification Still Matters
There are various characteristics and factors to consider when choosing the perfect lab-grown diamond for your forever ring, with certification being one.
Certification remains a crucial component when purchasing any diamond, whether laboratory-grown or natural. A grading report provides independent verification of a diamond’s characteristics and assures its authenticity and quality. Choosing a certified diamond offers peace of mind and reinforces confidence in your heirloom quality piece.
Both IGI and GIA continue to be the most recognised and trusted grading laboratories globally, and its reports remain widely used and respected within the jewellery industry. At TMC Fine Jewellers, we believe that transparency and education are essential, which is why we work with certification that allows you to clearly understand the quality of your precious gemstone.
Our Ethical & Certified Lab-Grown Diamonds
At TMC Fine Jewellers, every laboratory-grown diamond is hand selected by our Chief Gemstone Expert, alongside our Co-Founders. We choose to work with only the most superb lab-grown diamonds that deliver on our commitment of quality, ethicality and attainability. While grading methodologies may evolve, our standards do not.
All GIA laboratory-grown diamonds we work with fall within the ‘Premium’ classification, and our IGI-certified stones are D - F Colour, VS2-VVS1+ Clarity and Excellent Cut, Polish and Symmetry.
We believe luxury should never come at the cost of the world around us. By championing lab-grown diamonds and moissanite, we honour the balance of timeless elegance and ethical innovation. Every piece we create carries the promise of a better choice, for you, and for the future.
