Diamond Certification Comparison: GIA vs IGI

Diamonds are the most popular gemstones because of their unmatched beauty and remarkable durability. These stones are wonderful accents to any jewellery collection, whether used in earrings or engagement rings. 

Numerous factors exist when purchasing a diamond, including shape, fluorescence, and the four Cs. It used to be necessary to seek the assistance of a skilled jeweller to understand the various aspects of diamond quality and how they affect a particular diamond's durability, value, and appearance.

But because diamond certifications and reports are becoming increasingly common, it's now simpler than ever to comprehend the precise specifications of a particular diamond. 

Purchasing diamonds is no longer as mysterious due to organisations like the Gemological Institute of America (GIA) and the International Gemological Institute (IGI). These impartial grading laboratories evaluate loose diamonds and report on the best features using uniform measurements and guidelines.

This makes it simple for average consumers to peruse a large selection of gems and comprehend how they compare in the key areas of cut, colour, carat, and clarity. 

If you've never bought diamonds before, a little knowledge goes a long way. To compare GIA vs. IGI diamond certifications, we're looking at two of the most well-known diamond grading companies.

Regarding Diamond Certification

When diamonds are used to make jewellery, they are not always graded. Alternatively, several jewellery retailers and internet sellers decide to have their gemstones graded before listing them for sale. By doing this, you can give customers more power and transparency regarding the gemstones. 

When looking for diamond jewellery, many people will look for GIA or IGI-certified diamonds. This indicates that they are searching for diamonds that have had their 4Cs and other characteristics evaluated by the GIA or IGI.

Regarding Diamond Certification

Although GIA, IGI, and a few other businesses offer this service, the end product isn't precisely a certification. Rather, it's a diamond grading procedure that produces a report on diamond grading. 

There is frequent confusion between "diamond grading report" and "diamond certification." A diamond usually gets a grading report rather than a certification.

Experts compile these reports after thoroughly evaluating a diamond's essential characteristics. Other names, such as reports, dossiers, or grades, may refer to them. However, these reports are typically about a diamond's grading rather than a formal certification.  

Most people mistakenly search for graded diamonds when looking for certified diamonds. However, diamonds graded by reputable companies usually come with watermarked and traceable reports that feel much like certificates, so it's easy to get confused. A certified diamond is another term for a GIA or IGI grading diamond. GIA and IGI are the two most well-known organisations that grade diamonds.

How Does GIA Work?

GIA, also known as the Gemological Institute of America, is a nonprofit organisation headquartered in Carlsbad, California. The GIA was established in 1931 and is recognised for developing the industry-standard 4Cs diamond grading system.

For lab-created and natural diamonds, coloured gemstones, and pearls, they offer unbiased, precise reports based on laboratory testing. 

GIA offers a range of online and on-campus private education programmes at their locations worldwide, in addition to grading reports for gemstones. The Graduate Diamonds Programme, the Graduate Gemologist Programme, the Applied Jewellery Professional Programme, and the Jewellery Design & Technology Programme are among the programmes offered. 

GIA Diamond Certification

At GIA's independent labs, their highly qualified experts examine all gemstones and diamonds undergoing GIA grading. The diamond is assigned an internal identification number upon arrival at the lab to maintain its owner's anonymity and promote genuinely objective grading.

From there, precise measurement tools determine its dimensions, angles, and facets. Up to the fifth decimal place, the diamond carat is electronically weighed. 

The diamond is subsequently examined to ascertain whether it is artificial or natural. For colour grading, diamonds are also examined in a standardised viewing configuration. At this point, any treatments applied to a diamond will also be evaluated.

GIA Diamond Certification

Plotting any inclusions or points of interest using a 10x magnification is part of the GIA assessment, including clarity and finish. The diamond's dimensions, cut, and clarity are all marked on the gem's GIA report and verified by extra graders as needed.

After thorough analysis, the diamond's 4Cs and any extra characteristics are compiled on its report. In addition, GIA offers laser inscription as a grading option. The inscription is only visible at magnifications of 10x or higher.

A logo, the diamond's GIA report number, or even a personalised note on the gem's girdle or circumference can be included. 

This type of reporting makes it simple to comprehend the precise specifications of a given diamond by accurately illuminating its attributes on a standardised scale.

IGI: What Is It?

Originally, the IGI was the diamond industry's blue-collar workhorse. The International Gemological Institute (IGI) is the biggest independent lab for jewellery and diamond certification, having been established in 1975.

For the main jewellery chains in the US and Canada (Kay, Zales, etc.) they are the most well-liked gem lab. It's like a factory. Their rates are significantly lower than GIA's, and they operate quickly.

Compared to GIA, IGI has historically had laxer grading guidelines. Throughout the past ten years, IGI has worked to strengthen its grading. The standards employed in IGI's USA labs are frequently higher than those in Europe. We can only hope that they will get better still. For now, I would continue using GIA. They continue to be the benchmark for diamond certification.

The International Gemological Institute, or IGI, was established in 1975. The company is headquartered in Antwerp, Belgium. For diamonds, gemstones, lab-created diamonds, and completed jewellery pieces, IGI provides professional grading. Their grading schemes use impartial appraisals from jewellery specialists in controlled environments. 

In addition, they provide educational courses like the Retail Support Programme, the Jewellery Design Course, the Polished Diamond Course, and the Pearl Course. Numerous courses are offered at one of their campuses across the globe or online via their eLearning platform. 

IGI Diamond Scale

Every gemstone, diamond, and piece of jewellery that IGI grades is examined in a controlled laboratory environment. When it comes to diamonds, this entails a preliminary screening to ascertain whether the gem is naturally occurring or artificially created, as well as any permanent treatments the stone may have undergone.

After that, the diamond's cut, colour, carat weight, and clarity are expertly evaluated. All components are combined into an IGI report, which displays a plot of any inclusions along with each diamond's 4Cs rating. This report can be traced back to the labs at IGI and is available electronically. 

IGI Diamond Scale

For the diamonds it grades, IGI provides additional traceability and security. In addition to security seals and additional organisation during the grading process, the organisation provides screening and sorting services.

Some jewellers choose to have IGI engrave graded diamonds using their exclusive Laserscribe  service, which allows them to add a personal message, logo, or even the diamond's IGI report number to the gem's girdle or outer circumference.


There are a lot of similarities between IGI and GIA diamond grading services. GIA and IGI provide electronic reports that include the 4Cs and other noteworthy features for both naturally occurring and lab-grown diamonds. Additionally, each provides tiny inscriptions and their own special internal tracking numbers for their graded gems.

The GIA or IGI websites make it simple to check a diamond's report, and both organisations' reports can include images that highlight the specific characteristics of that particular gem.

Both businesses run their laboratories to examine gemstones impartially and employ unique, in-house methods. IGI offers grading for loose gems and entire jewellery pieces, whereas GIA concentrates on loose gemstones.

The most reputable source for accurate diamond grading has been the GIA over time.

GIA is the top option for diamond grading and certification due to its open grading processes, extensive history, and significant contribution to the global development of diamond grading practices. While there are certain parallels between IGI and GIA, no business can match the GIA grading process's precision, thoroughness, and openness.    

Two of the most respected and well-known diamond certification agencies in the world are IGI and GIA. Diamond grading reports, which provide details about a diamond's quality and characteristics, are offered by the GIA and IGI. There are, nevertheless, certain distinctions between the two certifications.

Grading Guidelines:

The grading guidelines for IGI and GIA are somewhat different. GIA is renowned for its rigorous grading system and is regarded as the industry standard.

Grading System:

The two organisations grade diamonds using a system that considers the four Cs: colour, clarity, cut, and carat weight. But IGI gives more weight to the diamond's cut, whereas GIA gives more weight to the diamond's colour and clarity.

Report Format:

The reports have distinct formats as well. A more comprehensive report with extra details like polish, symmetry, and fluorescence grades is offered by IGI. The GIA report is shorter and mostly concentrates on the 4 Cs.


The two organisations may charge different certification fees. IGI certification typically costs less than GIA certification.

The Unmatched Precision of GIA

It is believed that GIA invented the 4Cs and has continued to refine the process of accurately grading the most significant characteristics of diamonds. Apart from standardising the 4Cs as the gold standard for diamond grading, GIA has consistently employed cutting-edge technologies to measure numerous diamond elements with unparalleled accuracy. 

GIA-certified diamonds receive the most authentic grades possible because of GIA's ongoing commitment to maintaining anonymity throughout the grading process. The GIA is one of the most reputable diamond grading organisations, and its honesty and dependability are further cemented by increased transparency regarding review procedures and easily accessible fee schedules.

GIA-certified diamonds are among the most thoroughly examined stones on the market because they have undergone extensive scrutiny and unbiased analysis.

GIA-certified diamonds, or diamonds with GIA reports, are among the most precisely graded gems on the market. You can rely on a GIA diamond to be of the calibre specified in its comprehensive report.

The Value Of Diamond Classification

The diamond purchasing process is made less confusing by reports on diamond grading and certification. GIA and IGI reports facilitate diamond shopping by:

  • Clearly describing the quality of a diamond
  • Supplying information that can be useful for jewellery insurance plans
  • Facilitating the comparison of diamonds based on standardised factors
  • Settling any uncertainty regarding a particular diamond's 4Cs
  • Confirming if a diamond is artificial in a lab or natural
We take great pride in providing clear GIA diamond grading reports for natural and lab-created loose diamonds.  Contact us to speak with a non-commissioned expert if you have any questions about diamond grading or need assistance selecting the ideal gem.