Lab-Grown Diamond Certifications Compared: SGL, IGI, and More

As lab-grown diamonds gain popularity, understanding diamond certification becomes crucial for consumers. Much like natural diamonds, lab-grown diamonds require a reputable certification to ensure their authenticity, quality, and value. Among the many certification bodies, SGL (Solitaire Gemological Laboratories) and IGI (International Gemological Institute) are two of the most prominent. But how do these organizations compare, and what should buyers know before choosing their certified diamond?

In this blog, we’ll explore the top lab-grown diamond certifications, their grading standards, and what sets them apart.

1. Introduction: The Importance of Lab-Grown Diamond Certification

Certification is essential when purchasing a lab-grown diamond, just like it is for natural diamonds. Reputable certifying labs offer transparency regarding the diamond’s quality, ensuring buyers make an informed purchase. Certification reports assess the 4Cs — Cut, Color, Clarity, and Carat weight — and may also provide information about the diamond’s origin and the manufacturing process.

This blog will focus on two leading labs: SGL and IGI, as well as other notable certification bodies, helping consumers understand the importance of diamond grading and the differences between certifications.

2. Spotlight on SGL (Solitaire Gemological Laboratories)

Global Presence and Grading Standards

SGL operates in several countries, including India, the UK, the US, and Bangladesh. Known for its commitment to cutting-edge technology and international grading standards, SGL offers a comprehensive grading system.

SGL’s Grading Process

SGL uses an eight-step grading process for lab-grown diamonds:

1. Registration: The diamond is weighed, measured, and assigned a unique ID number.

2. Identification: Tools like DiamondSure™ and DiamondView™ are used for authenticity checks.

3. Cut Grading: The diamond is assessed on cut quality (excellent, ideal, or unusual).

4. Clarity: Three independent gemologists examine the diamond at 10X magnification.

5. Color Grading: Three gemologists assess color using the D-Z scale.

6. Optical Symmetry: Some diamonds with exceptional cuts exhibit hearts and arrows patterns.

7. Laser Inscription: Identification numbers are inscribed onto the girdle of the diamond.

8. Reporting: A detailed certificate is issued, including a diagram of clarity characteristics.

Reputation and Recognition

While SGL is well-regarded, particularly in India, it may not have the same global recognition as GIA or IGI. In some circles, SGL certifications are considered to be slightly lenient, particularly in terms of color and clarity grading.

3. Deep Dive into IGI (International Gemological Institute)

A Global Leader

IGI, established in 1975, is one of the largest independent gemological labs globally, offering certifications for both natural and lab-grown diamonds. IGI was the first to offer full grading reports for lab-grown diamonds.

IGI’s Grading Process

• 4Cs Grading: IGI uses a standardized D-Z color grading scale, where D is colorless and Z indicates light yellow or brown. For clarity, they grade from Internally Flawless (IF) to Included (I3).

• Cut Grading: IGI assesses polish, symmetry, and proportions to determine the cut grade. For round brilliant cuts, the grade ranges from Excellent to Poor.

• Growth Process Information: IGI provides details on the growth process (whether CVD or HPHT) used for lab-grown diamonds, offering greater transparency.

IGI’s Market Influence

As the most recognized lab for lab-grown diamonds, IGI holds significant sway, particularly with major retailers. While some critics argue that IGI’s grading may be slightly more lenient than GIA’s, it is still widely regarded as trustworthy for lab-grown diamonds.

4. Comparing Certifications: A Detailed Analysis

Grading Parameters Comparison

Additional Features

• SGL: Laser inscriptions, OriginAssure and EcoAssure programs for sustainability.

• IGI: Laserscribe service for engraving, detailed reports, and growth process transparency.

• GIA: Strict grading standards; digital-only reports for lab-grown diamonds.

• GCAL: 8X Cut Grade system, detailed light performance analysis, money-back guarantee.

• HRD Antwerp: Double coding system, laser inscription services, known for European presence.

5. Market Perception and Consumer Confidence

SGL: Although well-recognized in specific regions, SGL is less recognized globally compared to IGI or GIA. Some buyers feel SGL’s grading may be slightly lenient, particularly in color grading.

IGI: Highly trusted, particularly within the lab-grown diamond segment. It has widespread market acceptance and is often the choice for major retailers, although slightly more lenient than GIA.

GIA: Known as the gold standard in the diamond industry, GIA’s grading is viewed as rigorous and consistent, though it currently has fewer color/clarity categories for lab-grown diamonds.

GCAL: GCAL is recognized for its 8X cut grading system and is becoming popular for cut quality assessments. It offers a money-back guarantee, which adds confidence for buyers.

HRD Antwerp: Well-known in Europe but not as prominent globally. It is recognized for its grading reliability, especially for natural diamonds, and now applies those same standards to lab-grown diamonds.

6. Choosing the Right Certification for Your Lab-Grown Diamond

Choosing the right certification for your lab-grown diamond is a personal decision that depends on several factors:

• Brand recognition: GIA and IGI are widely recognized, with GIA being the most prestigious.

• Grading transparency: If you're looking for color and clarity transparency, IGI offers more detailed information about the growth process.

• Ethics: Certifications like SGL’s OriginAssure and EcoAssure may appeal to buyers who prioritize sustainability.

• Cut quality: GCAL’s 8X Cut Grade system is ideal for buyers who want a detailed assessment of the diamond’s brilliance.

Ultimately, GIA and IGI remain the most popular and trusted certifications for lab-grown diamonds, but SGL, GCAL, and HRD Antwerp offer valuable alternatives, each with its own unique features.

Make sure to choose a certification that aligns with your quality expectations, budget, and ethical values.