Are Lab Grown Diamonds GIA Certified?

Lab grown diamonds have been around since the 1950s, only twenty years after the inception of the Gemological Institute of America (GIA). After years of development, and decades of creating jewellery quality stones, lab grown diamonds finally became a GIA certified and graded gemstone in 2007

As of 2019, GIA dropped the word “synthetic” when referring to lab grown diamonds. This is another great step in recognising why lab grown diamonds are as good (if not better) than their mined counterparts. 

Lab grown diamonds are, in fact, real diamonds. Unlike cubic zirconia, man-made diamonds have the exact same chemical structure as natural diamonds. In all ways but their formation, they are true diamonds. So are lab grown diamonds GIA certified? Let’s find out.


What Is The GIA? 

The GIA (short for Gemological Institute of America) is one of the world’s leading authorities on gemstones and jewellery. They were founded in 1931, and since their very beginning have been furthering the world’s understanding of the miraculous and beautiful stones we find in our earth. 

In 1953, GIA issued their first diamond grading reports, which would soon become the industry standard. Even now, GIA’s first grading criteria - which included the now-famous 4Cs of diamond evaluation - is still used for your everyday jewellery.

To say the GIA has defined the jewellery industry is an understatement. For gemstones to be properly valued they must be properly graded, and the GIA has given us a widespread system we can use to compare all stones fairly.  

Aside from grading and evaluation (and we’ll get into exactly how diamonds are graded in a moment), the GIA is also known to undertake research and develop gem grading equipment. Quite the resume! There’s no doubt that having lab grown diamonds officially certified and graded by GIA is a huge step for the jewellery industry.

How Are Diamonds Graded?

Gem grading systems are used to determine the value and price of a given gemstone. Diamonds, like all gemstones, are graded using four criteria: colour, clarity, cut and carat weight. This system was developed by the GIA, and has become known as the Four Cs method.


A diamond's colour is a highly important factor in determining its value. For clear diamonds, the less colour a diamond has, the higher its colour grade. A diamond's colour is graded from D-Z with D being the highest possible grade or whitest colour. 

If a diamond's colour is slightly yellow or brown, its colour will be graded lower than one with no noticeable colour. This doesn’t mean every jewellery quality diamond you see is colourless, however; many diamonds do actually have some trace of colour that can lower the colour grading, even if the difference can’t be seen by the naked eye.

The colour of a diamond can have a dramatic effect on its price, because the whiter the diamond the more rare and valuable it is. Of course, a truly clear diamond is also unmistakably beautiful, and as desirable as any other stone on the planet.


Clarity refers to the appearance of internal and external flaws in the diamond, which are called inclusions and exclusions. Inclusions are the most common type of flaw, and can appear as cloudiness inside the diamond, or more noticeable lines and gaps. 

The most valuable diamonds are those that are most transparent and clear. If a diamond has blemishes, it is considered less valuable than other diamonds of the same size and cut. Almost all diamonds have inclusions or flaws, but the fewer there are, the more valuable they become.

Clarity gradings can go from flawless (FL) to Imperfect (P1, P2, P3).

Learn more: do lab grown diamonds have inclusions?



A diamond’s cut is considered the most important of the Four Cs on determining value, as it has the biggest effect on the way it catches light and sparkles. 

The cut grading of a diamond is a careful examination of its symmetry, polish and balance. The better the stone is cut and polished, the better the brilliance and scintillation of the stone. The balance of weight and durability is also considered in this part of grading.


The carat weight of a diamond is the measure of how much a diamond weighs. One carat is equal to 0.2 or one fifth of a gram. 

The size and weight of a diamond can have a dramatic impact on its price, but a bigger stone isn't necessarily better if it doesn’t have strong colour, clarity or cut gradings.


GIA will also check their diamonds for fluorescence, which causes diamonds to glow under UV light. While this isn’t part of the Four Cs and does not affect the value of a diamond, it is an interesting characteristic that can make a diamond truly unique. 

Learn more: do lab grown diamonds have fluorescence?

Are Lab Grown Diamonds GIA Certified?

So, are lab grown diamonds GIA certified? Yes, GIA has been evaluating lab grown diamonds since 2007, though they’ve had a history of researching and reporting on them long before then. Lab grown diamonds are graded the exact same way as mined diamonds, with evaluations of colour, clarity, cut and carat weight. 

Lab grown diamonds can be valued very highly depending on these characteristics, but will still cost less than a mined diamond of the same quality. This means that you can buy higher quality lab grown diamonds for much more affordable prices than their mined counterparts. 

All diamonds are carefully examined and tested for any sort of growth marking that might identify them as lab grown, and check if any colour or clarity enhancing treatment has been used. This is great for diamond buyers, as thorough checking means you’ll know exactly what you are buying. GIA will also identify which process was used to create the lab grown diamond, and include this information in their evaluation.

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