When shopping for diamond jewelry, one of the most important factors to consider is the diamond’s certification. The certificate provides detailed information about the diamond’s quality characteristics. There are several major diamond grading labs that issue certificates, but two of the most common are the Gemological Institute of America (GIA) and the International Gemological Institute (IGI). So how do IGI certified diamonds compare to those certified by GIA? Is it worth opting for an IGI stone? In this article, we’ll take an in-depth look at IGI diamond certification and help you decide if IGI diamonds are worth the investment.
Introduction to IGI Diamond Certification
The International Gemological Institute (IGI) is a leading independent diamond grading laboratory founded in Antwerp, Belgium in 1975. IGI has laboratories located in major diamond trading centers around the world including New York, Hong Kong, Mumbai, Bangkok and Tokyo. The institute issues diamond reports for loose diamonds that document the 4Cs (carat weight, cut, clarity and color) as well as other supplemental information. More than 2 million IGI diamond reports are issued each year.
IGI diamond reports include detailed maps of any inclusions present in the diamond. They also come with diagrams of the diamond’s proportions which indicate the quality of the cut. One key difference between IGI and GIA reports is that IGI includes a “light performance” grade. This measures how well the diamond’s cut refracts and returns light to the viewer. IGI reports have security features like watermarks and a unique report number to prevent duplication or forgery.
IGI Diamond Grading Accuracy
One of the main concerns surrounding IGI certified diamonds is whether their grading standards are as stringent and accurate as other labs like GIA. Numerous studies have compared diamonds certified by IGI and GIA to determine if there are significant inconsistencies:
| Study | Results |
|---|---|
| Gem Testing Laboratory (GTL), London, 2009 | 95% correspondence in grading between IGI and GIA |
| HJZ Gem Identification Center, China, 2017 | 92% alignment for color grade; 84% for clarity |
| Gemological Science International, 2004 | Less than 2% variance in measurements between IGI and GIA |
While there were some minor inconsistencies, these studies found a high rate of alignment overall between the two labs. Many in the industry consider IGI grading to be accurate and reliable, though slightly less stringent than GIA in some categories. This perception can lead to IGI stones being priced 10-15% lower than GIA certified diamonds of comparable specs.
Pros of Choosing an IGI Certified Diamond
Opting for an IGI graded diamond over one certified by GIA has some potential advantages:
- Lower price – You can potentially save 10-15% compared to a similar GIA diamond.
- Wider stone selection – IGI certifies a broader range of diamonds, including some GIA might not.
- Light performance grade – IGI is the only lab that includes this useful cut quality measurement.
- Buyback policies – Many IGI diamond retailers offer buyback guarantees if not satisfied.
- Resale value – IGI stones tend to hold resale value well as long as graded optimistically.
The potential cost savings are the main reason customers choose IGI over other diamond certification labs. You can get a beautiful, high quality diamond with an IGI report for less than a comparable GIA certified stone.
Cons of Opting for an IGI Diamond
There are also some potential downsides to selecting an IGI certified diamond:
- Occasional overgrading – Some studies show IGI grades can be slightly more optimistic in certain areas.
- Prestige factor – GIA certification is more prestigious and globally recognized.
- Resale concerns – A very small minority of buyers distrust IGI grading even though it is accurate.
- Not as widely known – GIA is a more established and well-known lab to many consumers.
The possibility of slightly generous grading is probably the most significant issue to be aware of if buying an IGI certified diamond. Reputable retailers address this by sticking to strict standards so all diamonds match their reports.
IGI vs. GIA Grading Comparison
Let’s take a closer look at how IGI and GIA compare when evaluating and certifying diamonds:
| Category | IGI Certification | GIA Certification |
|---|---|---|
| Grading Accuracy | Very accurate but occasionally overgrades cut and color | Considered the industry gold standard for consistency |
| Grading Standards | Slightly more lenient cut and color thresholds | Strictest and most consistent grading |
| Recognition and Prestige | Well-respected but less widely known by general public | Most iconic and globally recognized diamond certificate |
| Security Features | Watermarks, proprietary logo, unique report number | Microscopic inscription, proprietary logo, unique report number |
| Information Provided | 4Cs, clarity plot, cut diagrams, light performance | 4Cs, clarity plot, cut diagrams, fluorescence |
| Price | 10-15% discount vs. equivalent GIA diamond | Slight premium over equivalent IGI diamond |
In general, IGI offers very high quality grading and diamond certification. However, GIA remains the most prestigious lab worldwide with the strictest standards. IGI presents an excellent value for shoppers who prioritize cost savings.
Tips for Buying an IGI Certified Diamond
Follow these tips when shopping for an IGI graded diamond:
- Review the IGI report thoroughly – Check the 4Cs, diagrams, etc. Make sure it matches the seller’s description.
- Buy from a reputable retailer – Established jewelers are likelier to follow strict grading standards.
- Select ideal cut stones – Choose ‘excellent’ or ‘ideal’ cut grades for maximum light performance.
- Compare prices – Research diamond prices online to identify good deals.
- Avoid drastically discounted stones – Deeply discounted IGI diamonds may reflect overgrading issues.
- Consider a buyback policy – Many retailers offer buyback guarantees which add reassurance.
- Get an independent appraisal – If concerned, have the diamond evaluated by another gemologist.
Doing your due diligence when shopping can help ensure you select a high quality IGI certified diamond offered at an appropriate price point.
The Bottom Line – An IGI Diamond Can Be a Smart Purchase
IGI certified diamonds offer shoppers an excellent opportunity to save money without sacrificing quality. While the institute may not be quite as prestigious as GIA, it is still highly respected and issues accurate, dependable grading reports. As long as you purchase from a reputable retailer, an IGI diamond can represent outstanding value compared to a similar GIA stone. Just be sure to review the IGI grading thoroughly and buy a diamond that matches the report. For many shoppers, going with an IGI certified diamond is a smart decision that provides beautiful, expertly graded diamonds at more affordable prices.