IGI Certification Guide

IGI, the International Gemological Institute, is an independent gemological laboratory that issues grading reports for natural diamonds, laboratory-grown diamonds, gemstones, and finished jewelry. For lab-grown diamonds, an IGI report can confirm laboratory-grown origin and document important quality characteristics such as measurements, carat weight, color, clarity, and cut information where applicable.

What is an IGI diamond grading report?

An IGI grading report is an independent gemological document describing the characteristics of a submitted diamond or jewelry item. It is designed to provide standardized information that helps buyers, jewelers, and appraisers identify and compare diamonds using consistent terminology.

What an IGI laboratory-grown diamond report may include

• Laboratory-grown origin designation
• Shape and cutting style
• Measurements and proportions
• Carat weight
• Color grade
• Clarity grade
• Cut grade or cut assessment where applicable
• Polish and symmetry
• Fluorescence information where reported
• Comments regarding growth process or treatments when applicable
• Report number used to identify and verify the document

How IGI identifies laboratory-grown diamonds

Gemological laboratories use specialized testing and trained gemologists to determine whether a diamond is natural, laboratory-grown, or a simulant. Laboratory-grown diamonds can have physical and optical properties comparable to natural diamonds, so origin identification requires methods beyond normal visual inspection.

IGI grading for loose diamonds

When a loose laboratory-grown diamond is submitted for grading, the laboratory can directly evaluate measurements and the 4Cs without a mounting obstructing the stone. The report can also include polish, symmetry, fluorescence, and other identifying details depending on the report type.

IGI reports for finished jewelry

IGI also issues reports for finished jewelry. Because mounted stones cannot always be examined in the same way as loose diamonds, the report may describe the jewelry article, identify mounted gemstones, note precious metal content or purity marks when present, and document diamond characteristics to the extent the mounting permits.

IGI certification and laser inscriptions

Many graded diamonds can carry a microscopic laser inscription on the girdle that corresponds with the laboratory report number. The inscription is intended to help connect the physical diamond with its report. Whether an inscription is present should be confirmed on the specific grading report.

How to verify an IGI report

Use the report number shown on the document to check the report through IGI’s official verification service. The digital record should correspond with the identifying information shown on the grading document.

IGI grading report vs. jewelry appraisal

A grading report and an appraisal serve different purposes. A grading report documents gemological characteristics such as origin, measurements, and quality grades. An appraisal estimates monetary value for purposes such as insurance or replacement. A grading report can support an appraisal, but it is not itself a valuation.

How to read an IGI lab-grown diamond report

1. Confirm origin. Check that the report identifies the diamond as laboratory-grown.
2. Review measurements and carat weight. These describe physical dimensions and weight.
3. Read color and clarity together. They describe different aspects of appearance.
4. Review cut-related information. For applicable shapes, examine cut assessment, polish, symmetry, and proportions.
5. Read the comments. Growth process, treatments, inscriptions, or other information may be disclosed there.
6. Verify the report number. Confirm the report through IGI’s official lookup service.

IGI certification at Lunéa Paris

IGI documentation is product-specific. Not every Lunéa Paris style is individually IGI certified. When certification is included, the product page should identify it and provide the applicable report information. Always use the specific product details as the source of truth for what documentation accompanies a piece.