Diamonds are often called “forever,” but lasting confidence in a diamond often hinges not just on sparkle, but on credibility. That’s where grading laboratories like IGI and GIA come in.

In this post, we’ll compare IGI vs GIA, show where each shines, and how Solomon & Co. leverages both certification and craftsmanship to offer you the best in natural diamonds, lab‐grown diamonds, and Moissanite jewelry.

When you purchase diamond jewelry, you’re not just buying sparkle, you’re buying trust, value, and assurance. A certificate from a trusted lab lets you know exactly what you’re getting. Without it, a diamond might be overgraded, misrepresented, or difficult to resell or insure. The two names you’ll most often hear are IGI and GIA. But how do they differ? Which is “better”? And more importantly, how can you use that knowledge to choose a superior piece from a trusted jeweler like Solomon & Co.?

What Are IGI & GIA? (Origins & Missions)

IGI (International Gemological Institute)

  • Founded in 1975 in Antwerp, the IGI has grown to become one of the largest independent gemological labs globally.
  • It provides services including grading, identification, appraisal, and education.
  • Particularly popular in the jewelry trade, IGI handles both loose stones and finished jewelry.

GIA (Gemological Institute of America)

  • Established in 1931, GIA is a non‐profit institution that has become the benchmark in gemstone grading and education.
  • GIA created the modern 4Cs (Cut, Color, Clarity, Carat) standard for diamond grading, and continuously invests in research and education.
  • It maintains strong independence and is widely respected globally.

The 4Cs & Grading Philosophy

Both IGI and GIA use the 4Cs, Cut, Color, Clarity, and Carat, as the basis of their grading. However, how strictly they apply them can vary.

  • Cut often has the greatest effect on sparkle and brilliance.
  • Color grades how “white” or colorless the diamond is (for white diamonds).
  • Clarity considers internal inclusions or external blemishes.
  • Carat is the weight/size of the stone.

GIA’s grading philosophy is generally more conservative: they may grade down color or clarity more strictly, meaning a diamond may receive a “lesser” grade from GIA than IGI for the same stone. IGI is sometimes perceived as more lenient or “inflated” in certain markets.

That said, over the years, IGI has made efforts to tighten and standardize its grading.

IGI Strengths & Use Cases

Here are areas where IGI often excels:

  • Lab-Grown Diamonds (LGDs): IGI is a prominent lab in certifying lab-grown diamonds.
  • Lower Cost & Faster Turnaround: IGI certification is generally less expensive and quicker than GIA.
  • Appraised Value Inclusion: Some IGI reports include appraised value segments, useful for insurance.
  • Trade Familiarity: Many jewelry chains and manufacturing setups use IGI because of its accessibility and handling of finished pieces.

For buyers on a tighter budget or seeking lab-grown diamonds, IGI can be a practical choice, so long as you're aware of the nuances.

GIA Strengths & Use Cases

GIA’s advantages are strong and enduring:

  • Global Trust & Prestige: GIA certification is accepted worldwide as a gold standard, it adds credibility, especially for resale or cross-border sales.
  • Strict & Consistent Standards: Because of its conservative grading, a GIA grade often commands greater confidence that you’re getting what the report says.
  • Resale & Market Value: Diamonds with GIA reports may retain or fetch better value since buyers and dealers trust GIA’s rigor.
  • Lasering & Security: GIA often includes laser inscriptions matching the report number on the diamond’s girdle so the stone and document correspond.

For high-value natural diamonds or pieces intended for long-term legacy or resale, GIA is often the safer choice.

Key Differences: IGI vs GIA (Comparative Analysis)

Aspect/Feature GIA IGI
Full name/Establishment Gemological Institute of America; founded in 1931 International Gemological Institute; founded in 1975
Organizational type/Orientation Non-profit/independent, strong reputation as the “benchmark” in gemology For-profit/commercial, broad focus on both natural and lab-grown diamonds
Primary focus/domain Historically, natural (earth-mined) diamonds; now also grades lab-grown diamonds (with evolving approach) Both natural and lab-grown diamonds; often seen as a leader in lab-grown diamond certification
Adoption/market recognition Widely recognized globally; many high-end and investment buyers prefer GIA-certified stones Very well known, especially in Asia/Europe/retail markets; widely used for lab-grown stones
Grading strictness/conservatism Generally more conservative and stricter, especially in color and clarity; tends to “downgrade” more in ambiguous cases Slightly more lenient in grading; diamonds may receive a higher grade (by color/clarity) compared to GIA under similar conditions
Consistency/grading variance Strong consistency; smaller internal variance in grading across different stones/batches Some higher variance; slightly wider tolerances in certain parameters
Turnaround time (report issuance) Generally longer, due to rigorous checks and multiple graders Faster — IGI often offers quicker turnaround to accommodate retail and high-volume needs
Cost of certification Higher Lower — more economical, especially for lab-grown diamonds
Report content/detail Comprehensive: includes 4Cs (Cut, Color, Clarity, Carat), proportions, fluorescence, inclusion plot, etc Also includes 4Cs and many detailed parameters; sometimes with additional retail-oriented info (e.g. light performance)
Treatment/grading of lab-grown diamonds (LGD) Recently changing approach: from October 2025, GIA will adopt new grading framework (e.g. “Premium”/“Standard”) and move away from traditional nomenclature for LGDs Continues to use the traditional 4Cs approach for both natural and lab-grown diamonds; more established in LGD grading
Effect on price/premium/valuation Stones with GIA certificates often command a premium in the secondary/resale market (especially for natural diamonds) Because of more lenient grading and lower cost, IGI-certified stones may be priced lower (~8–12% on average) versus GIA for equivalent stated grades
Resale/liquidity/trust in secondary market Higher — many buyers, appraisers, and auction houses favor GIA for its reputation and stricter grading Moderate — accepted widely, but for high-end or investment stones the premium and trust may tilt toward GIA
Global lab network/locations Select labs worldwide; strong presence in major diamond trading centers Many labs and offices globally, especially in Asia/Europe/retail hubs
Security/verification/anti-fraud features Strong security, anti-tamper features, verification systems Also includes multiple security features (e.g. microprinting, holograms) and report verification systems
Reputation among experts/industry Considered the benchmark “gold standard” certification in many markets Respected, especially for retail and lab-grown markets, but often viewed as slightly “softer” in very high-end/investment segments
Best use/recommended scenarios For natural diamonds, high-value stones, investment/resale concerns, or when maximum certainty is needed For lab-grown diamonds, retail purchases, budget-conscious buyers, faster turnaround
Typical difference in grading (color/clarity) observed Tends to be stricter; a diamond might be graded one or more steps lower under GIA compared to IGI for the same stone Tends to give a bit “higher” grade under similar conditions, due to more lenient tolerances
Statistical comparisons/studies In studies, GIA is shown to have lower variance, more conservative grading In some comparative studies, IGI and GIA agree within 1 grade in most cases; differences occur more in borderline or ambiguous stones

One recurring observation in the trade: IGI‐graded diamonds often trade at a 12–20% discount compared to “equivalent” GIA-graded stones, even when visually similar. That reflects the market’s premium on GIA’s perceived rigor.

Yet, that doesn’t mean IGI is “bad”, many consumers find excellent value in carefully selected IGI stones (especially smaller sizes or lab-grown). The key is knowing how to scrutinize the certificate, confirm inscriptions, and compare apples to apples.

Recent Changes & Trends (especially for Lab-Grown Diamonds)

The diamond certification landscape is evolving, particularly for lab-grown diamonds (LGDs):

  • GIA’s New LGD Grading Framework: Starting October 1, 2025, GIA will stop using the traditional 4Cs nomenclature (D–Z, clarity grades) for lab-grown diamonds. Instead, LGDs will be classified under simpler labels like “Premium” and “Standard” to reflect their narrower range of variation.
  • IGI Keeps the 4Cs for LGDs: In contrast, IGI continues to certify lab-grown diamonds using the 4C system (cut, color, clarity, carat).
  • IGI Expansion in India: To support growing LGD demand, IGI is expanding its facilities in Surat’s Hira Bourse, bolstering its presence in India’s diamond hub.
  • Shifts in Trust & Standards: As certification models change, consumers must stay updated so that they understand whether the grading paradigm still matches value and expectations.

In short, for lab-grown diamonds especially, certification standards are in flux, making it all the more important to buy from a jeweler who stays on top of these changes, like Solomon & Co..

How to Use Diamond Certificates Wisely

A certificate is only as good as how you read and verify it.

Here are practical steps:

  1. Check Laser Inscription
    The diamond’s girdle should have a microscopic laser inscription matching the report number. This ensures the certificate belongs to the stone.
  2. Verify the Report Online
    Most labs allow you to enter the certificate number on their website to confirm validity.
  3. Compare to Known Standards
    Use the 4Cs to cross-check report values against market norms or trusted databases.
  4. Use Qualified Appraisals
    For insurance or resale, a third-party independent appraisal can validate the graded value.
  5. Beware of “Upgrades” or Regrading Pressure
    Some sellers may suggest regrading to get a better grade; always stay cautious and request transparency.
  6. Understand Lab Distinctions
    A "GIA" report from a less-reliable regional lab is different from one from a full GIA lab, always check lab location and credentials.

When certificates and the actual stone align, you gain confidence. That’s what Solomon & Co. ensures in every piece.

Natural vs Lab-Grown vs Moissanite Diamonds

Let’s briefly compare these three kinds of gemstone options you may see in Solomon & Co.’s catalog:

Type Definition/Source Pros Considerations/Drawbacks Role of Certification
Natural Diamond Mined from Earth over aeons Prestige, traditional value, emotional legacy Higher cost; environmental/ethical concerns in sourcing Certification (GIA or IGI) is central to verifying authenticity and quality
Lab-Grown Diamond (LGD) Created in lab (CVD, HPHT) More affordable per carat; same chemical & optical properties; sustainable Market shifts in grading (e.g. GIA’s new system), resale value may be different Lab certification is still critical, IGI is strong in LGD certs currently
Moissanite Silicon carbide gemstone, not diamond Brilliant sparkle, lower cost, durable Not a diamond, different refractive properties, not same resale market Certification may be from Moissanite specialist labs; transparency is important

Solomon & Co. offers all three: Natural Diamond collection, Lab-Grown Diamond pieces, and elegant Moissanite jewelry. The approach ensures you can choose based on value, ethics, and aesthetic, without sacrificing trust.

Why Choose Solomon & Co.

Here’s why Solomon & Co. stands out in this landscape:

  • Certification Integrity: Whether natural or lab-grown, every piece is accompanied by a credible certificate (GIA, IGI, or appropriate lab).
  • Transparent Education: Explain to customers how to read the certificate, verify inscriptions, and understand differences like IGI vs GIA.
  • Broad Offering Across Gem Types: You can choose from natural diamonds for legacy pieces, lab-grown diamonds for sustainable brilliance, or Moissanite for budget brilliance.
  • Customization & Craftsmanship: Solomon & Co. offers bespoke designs, letting you select the stone + setting that fits your vision and budget.
  • Ethical Sourcing: Even for natural diamonds, they emphasize responsible sourcing and clarity in supply chain (diamond traceability).
  • Long-Term Support: Assist with reappraisals, upgrades, and after-sales services, every piece is backed by trust.

In short: Solomon & Co. doesn’t just sell jewelry, it sells confidence, backed by certifications and expertise.

Buying Tips: Certificate + Stone + Setting

To make the most of your investment:

  • Prioritize cut first, then color, clarity, and carat, a well-cut stone with slightly lower clarity often looks better than a poorly cut “higher grade.”
  • Match certificate strictness to your goals: If resale is critical, favor GIA; if value and budget matter, IGI is acceptable if vetted.
  • Ask for side-by-side comparisons: Compare IGI vs GIA graded stones of similar specs to see visual differences.
  • Choose settings that protect: For stones with inclusions, bezel or secure prongs help protect vulnerable parts.
  • Keep paperwork, appraisals & certificates safe: You’ll need them for insurance or resale.
  • Don’t overpay for “grade inflation”: Sometimes a slightly lower grade (e.g. H vs G color) is indistinguishable to the eye but dramatically cheaper.

Resale, Insurance, and Long-Term Value

Certificate-backed stones tend to command better resale prices. Dealers and buyers trust labs like GIA more. Even for IGI stones, if the certificate is genuine and the inscription matches, you retain credibility.

For insurance, most policies require a third-party appraisal and certified grading. Solomon & Co. supports you in obtaining those. For long-term legacy, natural diamonds with strong certificates may be more prized in many markets. But lab-grown is growing in acceptance, especially when backed by credible certification.

Conclusion

In the quest for brilliance, IGI vs GIA is not about which is “best”; it’s about which is most suitable for your needs, how well the certificate is used, and how trustworthy your jeweler is. With certification, inscription, and transparency, Solomon & Co. bridges that gap: offering natural, lab-grown, and Moissanite diamonds with integrity, craftsmanship, and value.

Explore Solomon & Co.’s collection today. Request certificates and verify inscriptions. Ask questions, compare stones, and choose brilliance with confidence.

FAQs

1. Is GIA always better than IGI?
Not necessarily. GIA is more conservative and globally trusted, but IGI offers good value, especially for lab-grown stones. What matters most is certificate authenticity, how strictly it’s graded, and your intended use (resale, legacy, personal enjoyment).

2. Which certificate does Solomon & Co. use?
Solomon & Co. works with GIA, IGI, or other credible labs, depending on the stone type, but always ensures you receive full documentation and verification support.

3. Will IGI grades inflate the stone’s perceived value?
IGI has been perceived as more lenient in certain color/clarity grades, which sometimes leads to an inflated appearance. But well-chosen IGI stones, especially when independently verified, can still represent excellent value.

4. Why is GIA changing its grading for lab-grown diamonds?
Because LGDs tend to cluster within narrower ranges, GIA is shifting away from the traditional D–Z and clarity scale for LGDs, instead classifying them as "Premium" or "Standard."

5. Does Moissanite need certification?
Yes, a reliable certificate from a recognized Moissanite or gem lab shows authenticity, quality, and ensures transparency. Solomon & Co. includes such documentation with its Moissanite collections.

6. Can you upgrade the diamond later?
Many jewelers (including Solomon & Co.) offer upgrade programs. Keep your certificate and appraisal records safely, and you may exchange them for a better stone in future with credit.

7. Which is better, GIA or IGI?

GIA is better; it’s stricter and more trusted worldwide for diamond grading.

8. Is an IGI certificate trustworthy?

Yes, IGI is trustworthy, but it’s slightly less strict than GIA in grading.

9. Why are IGI lab diamonds cheaper than GIA?

Because IGI grading can be a bit looser, and GIA certification adds more prestige and cost.

10. What are the top 3 diamond certifications?

  1. GIA (Gemological Institute of America)
  2. AGS (American Gem Society)
  3. IGI (International Gemological Institute)

11. Do IGI diamonds hold value?

They hold value, but usually less than GIA-certified diamonds.

12. Which diamond certification is best?

GIA is the best and most respected certification.

13. Which is better, SGL or IGI?

IGI is better; it’s more recognized and consistent than SGL.