IDL’S GEMSTONE GRADING STANDARDS AND METHODS

Here’s our comprehensive guide on the 4C's of diamond grading and the gemstone grading index.

Diamond Grading

C1:

Carat

The carat weight measures the mass of a diamond, one carat equals 0.2gr

C2:

Color

A diamond’s colour is measured by comparing with a set of master stones. The standard scale goes from D to Z.

C3:

Clarity

The clarity refer to the presence of internal and external characteristics in a diamond.

C4:

Cut

The refers to the angles and proportions of a diamond. It also refers to the finishing qualities, being symmetry and polish and the shape of the diamond.

Diamonds, esteemed for their enduring allure and brilliance, undergo grading based on four essential criteria: cut, clarity, color, and carat weight. Mastery of these foundational elements is paramount in discerning the inherent beauty and value of diamonds.

The above guide also extends its purview to encompass the gemstone grading index, offering discerning insights into evaluating the quality and attributes of diverse gemstones beyond the realm of diamonds.

GEMSTONE IDENTIFICATION AND GRADING

  • Color description
    (main body color and presence of modifications)
  • Transparency
    (transparent, translucid, opaque)
  • Measurements
    (carat weight)
  • Shape / cut description
  • Species and variety identification
  • Geographic origin determination, when possible
  • Evidence of enhancements / treatments
    (kindly refer the chart below)

Abbreviations for treatments and enhancements for Gemstone Grading

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