IGI vs. AGS Diamond Certification: Which is Better?

Diamonds have been around for centuries and while much has changed, including technological advancements, cut quality, and shape popularity, they are still seen as tokens of love and commitment–especially when used as the centerpiece of engagement rings.

For many people, purchasing a diamond is a once-in-a-lifetime experience, meaning it needs to be taken seriously and given a lot of thought and research before making the plunge. While understanding the 4Cs—cut, color, clarity, and carat weight—is necessary, it's equally important to grasp how diamonds are graded and what is included in a diamond grading certificate. A diamond’s grading certificate provides a comprehensive viewpoint of its quality, covering not only the 4Cs but also factors like proportions, symmetry, and fluorescence. All of these puzzle pieces come together to impact a diamond’s brilliance, durability, and market value.

Even in the more recent past, natural-mined diamonds were the only option for consumers. Natural-mined diamonds were formed over billions of years within the Earth and take quite a lot of effort and natural resources to mine. With the onset of modern technology, there are now lab-grown diamonds available, which are grown in controlled environments using methods like Chemical Vapor Deposition (CVD) and High Pressure High Temperature (HPHT). Lab-grown diamonds are physically, chemically, and visually identical to natural mined diamonds. The only true difference is how they are grown and their impact (or lack thereof) on the environment. For eco-conscious consumers, lab-grown diamonds offer a sustainable option, often at a more affordable price point.

As lab-grown diamonds became more prevalent, the diamond grading industry had to evolve. Historically prestigious grading laboratories, such as the Gemological Institute of America (GIA), did not jump at the opportunity to provide grading certificates for lab-grown diamonds. Because of this, newer labs gained popularity by offering what GIA would not. Grading reports for lab-grown diamonds can be different from natural-mined diamond grading reports because they can include information about how the diamond was grown and treated. Regardless of whether you decide to purchase a natural or lab-grown diamond, choosing a certified stone is incredibly important, as it helps you avoid surprises. Of course it will also give you additional valuable information on your diamond, such as where it came from and what its quality is. 

The Importance of Certified Diamonds  

Don’t be fooled by the size of a diamond. Despite their tiny stature, they are incredibly detailed and complex stones. They contain all sorts of secrets that aren’t visible to the naked eye and require high tech equipment to evaluate. They may have color variations, inclusions, or specific cut parameters that you wouldn’t be able to evaluate without a professional. This is where the importance of diamond grading laboratories comes into play. These labs are staffed with properly trained professionals who possess the necessary tools and experience to evaluate diamonds thoroughly. A certified diamond has been reviewed by one of these skilled employees, who takes the time to evaluate each and every aspect of the stone, from the 4Cs to the cut, proportions, symmetry, and light performance. 

Certification not only informs you about the stone before purchase but also provides peace of mind, ensuring you’re paying a fair price. Additionally, having the proper documentation can make resale easier if needed. It’s important that your certification is very clear if the diamond is naturally mined or lab grown, and all of the labs we are familiar with certainly provide this information clearly. 

Diamond Grading Laboratories  

There's a wide array of diamond grading labs available and making the decision of which to utilize is not an easy one. To help you make an informed choice, let’s take a closer look at two of the options for well known diamond grading organizations: the American Gem Society (AGS) and the International Gemological Institute (IGI).

International Gemological Institute (IGI)

The International Gemological Institute (IGI), established in 1975 in Belgium, was created to provide diamond and gemstone grading services in one of the world's largest diamond trading hubs. Over the years, IGI has expanded its reach globally, with locations in countries such as the United States and China. Known to be reliable for fast processing, IGI provides grading certificates for both natural-mined diamonds and lab-grown diamonds. It was also the first lab to provide grading certificates for lab-grown diamonds, so they essentially set the standard for the other labs. When it comes to lab-grown diamonds, IGI is an industry leader. IGI’s lab-grown diamond certifications include cut, color, clarity, and carat weight, as well as fluorescence and symmetry. 

American Gem Society (AGS)

The American Gem Society (AGS) was founded in 1934 by Robert M. Shipley, the same man who established the Gemological Institute of America (GIA). AGS has a focus on ethics and consumer protection. They are known for their strong adherence to accurate grading using a particular system. AGS’s grading is different from GIA because AGS was the first lab to utilize a numerical scale, where 0 is the highest and 10 is the lowest. It specifically refers to the cut grade of the diamond, which also affects the brilliance of the stone. AGS is highly respected and does provide reports for both natural and lab-grown diamonds, making it a reliable organization regardless of which type of diamond you plan to purchase. 

IGI vs. AGS

While AGS is renowned for its cut grading expertise and focuses heavily on light performance, IGI’s reports are more general, yet still detailed enough for consumers to be well informed about the diamond they are looking to purchase. Diamonds with an AGS certification have more detail, especially on the diamond cut, but IGI is straightforward and clear for the consumer looking for ease of purchase and possibly a lower budget alternative. Each lab focuses on different priorities and understanding their strengths can help you choose the certification that best meets your needs.

Which Certification is Right for You?

This is a very complicated question because there really is no right or wrong answer. Choosing between IGI and AGS (or any other diamond grading lab for that matter) depends upon your personal preferences and priorities. Your best bet would be to make a list of your priorities for the diamond you're looking for. Once you establish those, go with that lab that focuses more on your priorities. Not sure about your priorities. Here are some questions you may want to ask yourself:

• Are you more concerned about cost?

• Do you care about how quickly the certification is completed?

• Do you want a lab-grown or natural-mined diamond?

• Do you want to go with a lab that focuses more on cut or additional diamond specifications?

• Are you a stickler for strict grading or are you okay with a more lenient grading system?

Only you can truly answer these questions.

Both AGS and IGI provide valuable information on diamonds that you wouldn’t be able to determine on your own. That is a major benefit for either lab!

No matter which certification you select, making the decision to purchase a certified diamond will give you the peace of mind that you’re investing in a valuable object that will meet your expectations based on the information you’ve gathered.