GIA vs. GSI Diamond Certifications

by Ultimate Jewelry Guide
GIA vs. GSI Diamond Certifications

GIA and GSI are two of the most well-known diamond certification companies in the world. There are many reasons for this, but one of the main ones is that they offer a range of diamonds to suit every budget.

The only problem is that it can be difficult to figure out which company offers better quality service overall.

This blog post will compare these two diamond certification companies side by side so you know which one offers better quality diamonds!

What Is A Diamond Certification?

Diamond certification is the process of having a certain diamond graded by an expert in grading diamonds. There are two main types of certification: GIA and GSI Diamond Certifications.

What Is A GIA Diamond Certification?

GIA (Gemological Institute of America) is a diamond certification company that provides grading reports and other related services. GIA was established in 1931, with the aim to provide quality education on gemstones, diamonds, and jewelry to all levels from professionals through students. With over 80 years of experience under its belt, you can trust GIA diamond certification for your diamonds.

While the company’s main focus is certifying natural diamonds based on different factors, they’re also involved in other aspects of the diamond industry.

For example, GIA conducts research on diamonds and has a laboratory that is equipped with advanced equipment to do so. In fact, this lab’s instruments are considered some of the best in the world because they’re state-of-the-art technology.

And if you’re wondering what makes GIA Diamond certification the best, it’s because they’re the largest diamond testing and grading company in the world. Also, their reports are accepted all over the globe without question.

How To Read A GIA Diamond Report?

To read a GIA Diamond Report, you need to understand the grading scale used by this lab.

Gemological Institute of America’s (GIA) diamond grading system is one of the most widely accepted and respected systems in use today. The “Four Cs” — cut, color, clarity, and carat weight — are the universal characteristics by which diamonds are assessed and valued.

GIA’s diamond grading scale is based on a letter-grading system ranging from D to Z, where D represents colorless diamonds while Z grades indicate yellow or brown tinted stones that can only be sold at greatly reduced prices.

Besides this, there are some other additional factors that need to be considered while reading a GIA Diamond Report. Here are some of them:

Quality and Accuracy

The quality and accuracy of the images included in the report as well as any video content should be analyzed carefully as images can influence your opinion about a diamond stone significantly. Be sure that they correspond with the grading scale, otherwise, you might end up paying too much for a diamond.

The Report’s Tone and Language

Another thing you need to pay attention to is the report’s language and tone of writing, which should be professional enough to provide you with accurate information without causing any irritation or discomfort.

What Is A GSI Diamond Certification?

A GSI Diamond Certification is an independent certification that measures several key aspects of a diamond’s quality. The company behind this certification, Gemological Science International (GSI), was founded in 2005 and has since become one of the world leaders in gemology education for grading diamonds.

It’s not as experienced as the GIA diamond certification, but it does offer a good alternative. In fact, the GSI Diamond Certification has been quickly gaining ground in recent years and is often used by retailers to provide customers with diamond certifications that are not only accurate but also easy to read for all ages.

Should You Buy A GSI Certified Diamond?

Yes. You can purchase a GSI certified diamond but most experts suggest that you shouldn’t. Some diamonds with a GSI certification have been found to be associated with conflict. This means that the diamond was mined in an area where there is a high risk of human rights abuses or environmental damage. They were then sold on the black market as a way for criminals to make money off their stolen goods.

This can’t be said about all diamonds, but it is something to consider when making a purchase. Not only that, GSI certified diamonds have been associated with weak and loose grading. As a result, buyers are often disappointed with the quality of diamonds they receive.

So, you should approach your purchase with a critical eye. Look at the GSI certification and ask yourself if it is worth purchasing a diamond that was possibly mined in an area of conflict or has been associated with grading inconsistencies.

GIA vs. GSI Diamond Certifications – What’s the Difference?

It can be confusing when you see the letters GIA and GSI. What do they stand for? Is a GIA certification better than a GSI diamond certification?

There are many differences between these two popular diamond certifications that people should know about before making their final decision on which one to choose. The first thing is understanding what each of them actually stands for.

And now that we’ve cleared that part, let’s see how they differ based on different factors:


GSI is likely to grade diamond color one or two grades higher than the GIA. So, for example, if GSI designates a diamond’s hue as G, the GIA may give it an H or I. Those differences are tough to perceive without equipment, but sellers will charge more for a G-colored stone rather than the H and I.


The lower the clarity, the higher its grade; it is based on the number of inclusions visible to the naked eye and their severity. Because gemologists evaluate not only the types of inclusions but also their size and position, clarity is a subjective rating.

A VVS1 (very, very slightly included) clarity grade to one gemologist may be a VVS2 (very, somewhat included) to another. A higher clarity grade would result in a greater sales price.

The GIA is expected to grade clarity one level higher than the GSI. That means if a GIA diamond is graded VS2 clarity, you may anticipate a VS1 rating from the GSI. It’s not that GSI is giving an incorrect clarity determination. Because it’s a subjective measurement, there will be some variances.


The Carat weight of a diamond is an objective number determined by the GIA or GSI, so there’s no need to worry about differences between the two organizations. The gemologists simply weigh the stone on a scale and record the result.

Carat weight is the most important characteristic for determining the value of a diamond. Even a few hundredths of a carat make a significant difference in price. Before buying, verify the weight of a diamond with documentation.


The GIA and GSI way of classifying cuts differs somewhat. The following are the cut grades designated by GSI: Ideal, Excellent, Very good, Good, Fair, and Poor.

The GIA does not give an “Ideal” grade, therefore the highest grade possible is “Excellent.”

The distinction between a one-carat diamond and a two-carat diamond isn’t as simple to determine as the difference between a carat and a cut. However, there are more measurable criteria than clarity and color when it comes to evaluating diamonds.

While you may observe the same diamond having one cut grade higher when assessed by GSI versus GIA, you shouldn’t be concerned about consistent variances in this area.

A GSI grade of Ideal equates to Excellent from the GIA.

Why Do People Prefer GIA Certified Diamonds?

The GIA Diamond Certification is the most trusted and prominent diamond certification in the world. It’s globally accepted for its strict grading standards, making it a popular choice among buyers because of this trust factor.

Therefore, people prefer GIA Diamonds because they are confident that these diamonds have been graded to the highest standards.

How Does A Diamond Certification Affect The Price?

Diamond certification is one of the most important factors. A certified diamond has a higher value than an un-certified stone because it is graded and examined by experts to ensure that every characteristic matches the grading report provided.

The GIA (Gemological Institute of America) provides better quality diamonds than GSI, but they are both highly recommended when it comes to certification.

Diamonds that are not certified could be misrepresented in terms of quality, or they may have been treated with processes that would make them less desirable if the buyer knew about it. A diamond’s certificate will provide all details including clarity, cut grade, and carat weight so you can determine its value before purchase.

The price of a diamond will increase due to certification, but it is more because the value of the stone has been verified by experts. This is why industry professionals recommend GIA or GSI Diamond Certifications for all diamonds purchased.


In the end, it’s advisable to go GIA-certified diamonds compared to GSI. The differences in quality and grading are noticeable, but GIA certifications tend to be more respected by the industry professionals as a whole.

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