Gemstone Cutting Eliminating Green Table Effect
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Solution Overview
Problem
Despite modern tools and techniques, the 'green table effect' – characterized by low-intensity green light in the peripheral areas of diamond tables – often occurs in diamonds cut using standard methods, detracting from maximum light performance and being difficult to avoid or eliminate.
Innovation Solution
Adjusting specific combinations of angles and lengths of the lower halves, pavilion mains, and crown mains, such as amending the lower halves angle, length, and pavilion mains angle, to eliminate the green table effect, as determined by formulas and data presented in the patent, ensuring optimal light performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If standard AGSL cutting charts are used with 80% lower halves length, then manufacturing process is simplified, but green table effect appears in peripheral areas reducing light performance
Solution Approach 1:
The patent changes the lower halves length parameter from the standard 80% to a range of 73-77%, and adjusts the lower halves angle to be within 0.5 degrees of the pavilion mains angle. These parameter modifications eliminate the green table effect while maintaining ease of manufacture through updated cutting charts and software.
2Illumination intensity
If crown and pavilion angles are optimized for ideal light performance grade, then light return is maximized, but green table effect still appears in peripheral areas
Solution Approach 1:
The patent introduces additional parameter constraints beyond crown and pavilion angles. Specifically, it requires lower halves length to be 73-77% and lower halves angle to be within 0.5 degrees of pavilion mains angle. These additional parameter changes eliminate the green table effect while preserving optimal light return.
3Illumination intensity
If lower halves angle is made steeper to maximize light performance, then brilliance increases, but green table effect appears in peripheral areas
Solution Approach 1:
The patent constrains the lower halves angle to be within 0.5 degrees of the pavilion mains angle, preventing it from becoming too steep. This parameter change eliminates the green table effect in peripheral areas while maintaining optimal brilliance through the updated cutting specifications.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively eliminates the green table effect, achieving an AGS light performance grade of ideal 0 with enhanced light return and brilliance by precisely modifying the gemstone cut parameters.
Implementation Method 1
Using ASET imaging, as well as ray tracing and virtual diamond modeling software, the AGSL has determined the combinations over a range of table percentages, crown angles, and pavilion angles, that are needed to obtain ideal cut proportions for maximum light return or brilliance.
Implementation Method 2
ASET imaging can be used to generate light performance maps such as the ASET® maps by illuminating the gemstone with green, low angle light from the sides, in the upper hemisphere up to 45 degrees from the horizontal plane of the table facet
Data Source
AI summary
A precision hearts and arrows gemstone cut having an AGS light performance grade of ideal 0 and having an ASET image free or essentially free of green hemisphere light in the peripheral regions of the table facet; and methods for shaping the gemstone to eliminate the green table effect. The green table effect is avoided by using specific ranges of crown mains angles, pavilion mains angles, lower halves lengths, and/or lower halves angles, in accordance with specific values and/or mathematical formulae.