Many diamond buyers ask whether their diamond is IGI certified, but few actually know how to read the certificate.
Welcome to Know Your Jewelry series! Think of an International Gemological Institute (IGI) certificate as your diamond's official identity card—it outlines every detail of what you are purchasing.
Here is how to decode each key section of an IGI report:
1. IGI Report Number
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What it is: A unique identification number assigned to your diamond.
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How to verify: You can enter this number directly on the official IGI website to verify its authenticity. This same report number is laser-inscribed directly onto the diamond's girdle.
2. The 4 Cs (Grading Results)
The primary parameters determining a diamond's quality and value include:
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Carat Weight: The precise weight of the diamond.
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Color Grade: Evaluates the degree of colorlessness.
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Clarity Grade: Measures the presence of internal or external imperfections.
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Cut Grade: Refers to how brilliantly the diamond reflects light. An Ideal cut grade represents the highest quality craftsmanship; grades below ideal compromise brilliance.
3. Physical Dimensions & Finishing
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Measurements: Lists the exact dimensions (length, width, and depth in millimeters), showing the true physical size of the stone.
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Polish & Symmetry: Indicate how meticulously the diamond's facets were cut, smoothed, and aligned.
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Fluorescence: Describes how the stone glows or reacts when exposed to ultraviolet (UV) light.
4. Origin & Growth Method
For lab-grown diamonds, the IGI report explicitly confirms its lab-created origin. It also specifies the exact technology used to produce the gem:
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CVD: Chemical Vapor Deposition
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HPHT: High Pressure High Temperature
By understanding these parameters, you can review any IGI report with confidence and ensure you get exact value for your investment.
