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Quality & Standards7 min read

Deconstructing Grading Reports: GIA vs. IGI in Lab-Grown Diamonds

REPORT BYElena Rostova, Director of Quality Assurance
PUBLISHED ON June 20, 2026
Deconstructing Grading Reports: GIA vs. IGI in Lab-Grown Diamonds

In the B2B diamond trade, trust is established through documentation. While visual inspection under loupes can indicate quality, it is the grading reports from independent, authoritative laboratories that secure global transactions.

At Mira Gems, we subject our production to the most stringent international standards: the Gemological Institute of America (GIA) and the International Gemological Institute (IGI).

The Four Cs: CVD vs. Mined Parameters

A common misconception is that lab-grown diamonds require a different grading scale than mined stones. Because CVD diamonds are chemically and optically identical to mined diamonds, they are graded using the identical 4Cs system:

  • Carat Weight: Measured to the thousandth of a carat using high-sensitivity laboratory scales.
  • Color: Graded on a scale from D (completely colorless) to Z (light yellow or brown). Mira Gems focuses almost exclusively on the premium D-F range.
  • Clarity: Graded from Flawless (FL) to Included (I). Our CVD growth recipes optimize for high-pressure, inclusion-free crystallization, yielding VVS1 to VS2 levels.
  • Cut: The most critical factor for brilliance. We polish 100% of our round brilliant cuts to “Excellent” (GIA) or “Ideal” (IGI) proportions.

The Laser Inscription: Girdle Registries

Every certified diamond above 0.50 carats leaving Mira Gems undergoes micro-laser engraving on its girdle. This inscription is invisible to the naked eye, requiring 10-30x magnification to read.

A typical inscription contains:

  1. Lab Registry Number: E.g., GIA 1234567890 or IGI LG987654321.
  2. Growth Method Indicator: The text LAB GROWN or LG is always present, ensuring absolute transparency in compliance with FTC guidelines.

This laser inscription acts as a unique serial number, matching the digital certification records. If the girdle registry does not match the paper/digital certification exactly, the diamond cannot be exported.

API Integration: The B2B Digital Ledger

Modern wholesale purchasing has bypassed manual paper filing. To support automated procurement systems used by global jewelry manufacturers, Mira Gems has developed direct API connections to GIA and IGI ledger databases.

When a wholesaler places a bulk order:

  • They receive a structured CSV file containing all stone registries.
  • The file links directly to the lab’s digital API, allowing immediate verification of weight, color, clarity, and measurement parameters.
  • This eliminates manual entry errors and safeguards against counterfeit certification.

By establishing absolute data symmetry between our facility, the grading laboratories, and our buyers, we provide a seamless sourcing pipeline that wholesalers can audit instantly.