IGI vs GIA Certifications (Full Breakdown)

Last Updated on August 22, 2022

Selecting a high-quality diamond or gemstone is one of the most important decisions when it comes to purchasing a piece of jewelry.

Two prominent agencies, the International Gemological Institute (IGI) and the Gemological Institute of America (GIA), help consumers purchase diamonds and gemstones with confidence.

But what sets the two agencies apart and how do their reports compare to one another?

Here’s a look at the differences between IGI and GIA to help you better understand how both agencies grade diamonds and gemstones. 

1 Carat Total Weight GIA Certified White Round Diamond Solitaire Stud Earrings Pair set in Platinum 4 Prong Push Back (D-E Color VS1-VS2 Clarity)


What Is IGI?

IGI Certified 1 Carat Lab Grown Diamond Stud Earrings for Women in 14k White Gold with Secure Screw Back D-E Color by Beverly Hills Jewelers

The International Gemological Institute (IGI) is a Belgium-based gem agency that provides grading reports for colored and colorless gemstones.

Established in 1975, IGI is conveniently located near multiple gemstone mining regions and is the largest independent lab in the world.

Using a set list of grading criteria, IGI conducts a comprehensive evaluation of the physical characteristics of gemstones and provides an extensive report detailing the quality of the stones.

IGI is popular in Asian and European marketplaces, as well as with big-box jewelry retailers in the United States. 

IGI is known for upholding positive rapport with its vendors and offering low prices and fast delivery times.

All IGI reports include an authorization number that can be easily located within their database. 

Aside from providing grading reports to retailers, IGI is also a major contributor to research and education in the gemstone industry. 

What Is GIA?

2 Carat GIA Certified Cushion-Cut Classic Prong Set Diamond Engagement Ring with a 1 Ct G-H VS1-VS2 Center

The Gemological Institute of America (GIA) is the most well-known independent gemstone grading agency.

GIA specializes in assessing the quality of natural and lab grown diamonds, as well as colored gemstones.

Established in 1931, GIA is a non-profit agency that’s credited with establishing the set list of grading criteria based on the 4 C’s currently used by gemstone grading agencies around the world.

GIA has positive relationships with major online jewelry vendors, with exclusive contracts with some independent retailers who stock only GIA-certified diamonds and gemstones.

All GIA reports include a unique identification number that can be accessed on the GIA database. 

Aside from grading a variety of gemstones, GIA is known for being a leader in global gemstone research.

IGI And GIA Grading Reports

IGI and GIA are both reputable and well-respected gemstone grading agencies.

While both produce high-quality grading reports, there are a few fundamental differences between the two.

IGI Reports: What’s Included?

IGI reports grade colored and colorless diamonds using the 4 C’s of diamond grading:

  • Color
  • Cut
  • Carat
  • Clarity

Aside from the 4 C’s, IGI includes information about the diamond’s proportions, shape, cutting style, and measurements.

Colored diamond reports from IGI include an image of the stone and use a simple-to-read grading scale to determine the quality of the stone’s color and clarity.

GIA Reports: What’s Included?

Similar to IGI reports, GIA grading reports include a thorough assessment of the physical characteristics of the gemstone.

GIA reports follow the standard 4 C’s grading criteria and include additional focus on:

  • Inclusions
  • Polish
  • Symmetry
  • Fluorescence

GIA also utilizes a color grading scale to assess the color quality of colored diamonds and gemstones. 

Differences Between IGI And GIA Grading Reports

While both agencies are well-respected in the gem industry, there are a few fundamental differences between IGI and GIA grading reports.

GIA Grading Reports

GIA is considered the most reputable grading agency in the industry. This is because the agency applies strict laboratory standards to all grading activities.

Because of this, gemstones with a GIA grading report often sell for higher prices than gemstones with grading reports from other agencies.

However, it’s important to note that aside from carat weight, all gemstone grading criteria are subjective and dependent upon the expert who’s evaluating the stone.

Though gemstones graded by IGI typically receive a grading report 1-2 points higher than GIA, this does not mean one agency has better grading practices than the other.

Rather, the two agencies grade using subjective criteria based on the interpretation of the gemstone expert. 

IGI Grading Reports

While IGI cannot compete with the reputation of GIA, the agency is known as the top grading agency for lab grown diamonds.

IGI specializes in grading lab grown diamonds and works with many popular online retailers to grade large collections of lab grown diamonds.

IGI is also the first agency to certify the color and cut of lab grown diamonds and provides appraisals for diamonds based on similar criteria. 

While IGI may not be the go-to agency for natural diamonds, it’s certainly the top agency when it comes to providing high-quality grading reports for lab grown diamonds. 

Jackie Palmer is a Houston-based coin journalist and fashion enthusiast. She joined Jewels Advisor’s content team after years of experience as a content strategist, managing blogs and social channels for local stores. Jackie mostly collects and studies US coins produced during the 20th century and over the years, published hundreds of articles for multiple coin publications.