How to Read an IGI Certificate — Full Report vs Card Certificate
When purchasing a lab-grown diamond, an IGI certificate ensures authenticity and provides key insights into quality. However, not all certificates are the same. Here we explain the differences between a full IGI report and a card-type certificate, and why MadisonDia recommends the full report.
What is Included in an IGI Full Report?
The full IGI report contains comprehensive grading details, allowing consumers to evaluate their diamond with confidence. It includes:
- Cutting Style – Round Brilliant, Oval, Pear, Cushion, etc.
- Measurements – Millimeter dimensions of the stone.
- Carat Weight – Exact weight to two decimal points.
- Color Grade – From D (colorless) to Z (light color).
- Clarity Grade – From Flawless (FL) to Included (I3).
- Cut, Polish, and Symmetry – Detailed grading of craftsmanship.
- Fluorescence – Presence of UV fluorescence.
- Comments – Such as “No indication of post-growth treatment,” meaning the diamond has not undergone enhancements after growth. This assures transparency in quality.
- Growth Method – HPHT or CVD.
- Detailed Proportions – Including table %, depth %, crown angle, pavilion angle, girdle thickness, and culet size.
- Clarity Characteristics Plot – A map of inclusions and blemishes unique to your stone, similar to a fingerprint.
Recommended Proportions for Round Brilliant Diamonds
To ensure maximum brilliance and fire, experts recommend the following proportions:
| Parameter | Recommended Range |
|---|---|
| Table % | 54% – 57% |
| Depth % | 61% – 62.5% |
| Crown Angle | 34° – 35° |
| Pavilion Angle | 40.6° – 41° |
| Girdle Thickness | Thin – Medium |
| Culet | None – Very Small |
The 4Cs Charts
Diamond Color Scale
| Grade | Description |
|---|---|
| D – F | Colorless |
| G – J | Near Colorless |
| K – M | Faint Color |
| N – R | Very Light Color |
| S – Z | Light Color |
Diamond Clarity Scale
| Grade | Description |
|---|---|
| FL – IF | Flawless / Internally Flawless |
| VVS1 – VVS2 | Very Very Slightly Included |
| VS1 – VS2 | Very Slightly Included |
| SI1 – SI2 | Slightly Included |
| I1 – I3 | Included |
Diamond Cut Grades
| Grade | Description |
|---|---|
| Excellent | Optimal brilliance and fire |
| Very Good | High brilliance with slight differences |
| Good | Noticeable variations in brilliance |
| Fair | Limited sparkle |
| Poor | Dull, little brilliance |
Carat Weight
Carat weight measures diamond size, but brilliance depends more on proportions and cut quality. A well-cut 1.0ct diamond can appear larger and more brilliant than a poorly cut 1.2ct stone.
What is an IGI Card Certificate?
The IGI card certificate is also an official document but contains significantly less detail. It typically includes:
- Cut and Shape
- Carat Weight
- Color Grade
- Clarity Grade
- IGI Laser Inscription Number
-
However, it does not provide proportions, polish, symmetry, fluorescence, growth method, or clarity characteristics.
Full Report vs Card Certificate — Key Differences
| Feature | IGI Full Report | IGI Card Certificate |
|---|---|---|
| Cutting Style | ✔ | ✔ |
| Measurements | ✔ | ✘ |
| Carat Weight | ✔ | ✔ |
| Color Grade | ✔ | ✔ |
| Clarity Grade | ✔ | ✔ |
| Cut Grade | ✔ | ✘ |
| Polish & Symmetry | ✔ | ✘ |
| Fluorescence | ✔ | ✘ |
| Proportions | ✔ | ✘ |
| Clarity Characteristics Plot | ✔ | ✘ |
| Growth Method (CVD/HPHT) | ✔ | ✘ |
| Comments (e.g., No Post-Growth Treatment) | ✔ | ✘ |
Why MadisonDia Recommends the Full IGI Report
Although IGI card certificates are cheaper, our expertise shows that laboratories often reserve lower-quality stones for this option. For example, a diamond may have a D color and VVS1 clarity, but if the cut is poor, it will lack brilliance. By only issuing a simple card certificate, the lab avoids full grading exposure.
For consumers seeking long-term value and transparency, MadisonDia strongly recommends purchasing diamonds with a full IGI report. This ensures you understand the complete profile of your diamond and can be confident in both beauty and value.
