The International Gemological Institute (IGI) has introduced a new grading report for round brilliant cut diamonds, the Light Performance Grading Report.
This report focuses on the optical performance of diamonds, providing detailed insights into their visual properties.
Grading System and Metrics
The IGI Light Performance grading system employs a methodology that assigns an overall Light Performance score to each diamond. This primary score is supplemented by additional metrics assessing Brightness, Fire, and Contrast. These parameters are essential for assessing how diamonds interact with light, which affects their visual appeal and potentially their market value.
The system employs advanced ray-tracing software and slope proportions logic to assess a range of data for diamonds with varying table sizes. This scientific approach helps in quantifying the aesthetic characteristics that make each diamond unique.
In the IGI system: “Brightness” refers to all reflected and refracted white light. “Fire” is dispersed light seen as flashes of color. “Contrast” is the balance and intensity of light and dark areas at common viewing distances. The primary “Light Performance” score indicates the overall strength of brightness, fire, and contrast as they combine to produce scintillation; considered by many to be a diamond’s most appealing quality.
“Light performance is directly connected to a diamond’s appeal,” explains IGI CEO Tehmasp Printer. “In recent years we have seen increasing interest in expanded performance analysis. IGI has responded by creating an easy to understand, science-based light performance report along with cutting guidelines for diamond producers, empowering them to target the best results. We are pleased to support manufacturers, sellers, and buyers of high performing diamonds with detailed information on these popular aspects of diamond beauty.”
Technological Support and Analysis
An integral part of this grading system is the ‘Ideal-Scope’ instrument. This tool generates a visual representation of the diamond, showing factors such as light return, light leakage, and contrast patterns. These images align with the diamond’s measured parameters and aid in the analysis of its light behaviour.
Implications for the Jewellery Industry
The introduction of the Light Performance Grading Report by IGI offers an additional tool for diamond appraisal and is another asset to help potential customers understand their diamond. It complements traditional grading methods by providing a detailed analysis of a diamond’s interaction with light, enabling jewellers to better explain the distinctive qualities of each diamond to consumers, which may influence buying decisions.
Additionally, the provision of light performance cutting guidelines for diamond manufacturers might encourage improvements in diamond cutting practices, focused on optimizing light performance features.
For more information about diamond cutting guidelines, visit here
