Gemstone Doublet Detection Using Deep-UV Luminescence Comparison
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Solution Overview
Problem
Existing methods struggle to effectively identify doublet gemstones, particularly type IIa/IaAB diamonds, as they may pass initial screening and not be referred for advanced testing, making it difficult to detect synthetic material on the crown or pavilion.
Innovation Solution
A method involving ultraviolet radiation at 225 nm or less is used to irradiate the gemstone's upper and lower portions, capturing luminescence in specific time windows and comparing properties to characterize the composition, using luminescence color and pixel ratio analysis to distinguish between natural and synthetic layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If deep UV imaging instruments (DiamondView, SYNTHdetect) are used for screening, then synthetic diamonds can be detected, but doublet gemstones may pass initial screening undetected
Solution Approach 1:
The gemstone is divided into two portions (crown and pavilion) and each is irradiated and analyzed separately. By comparing the luminescence properties of these segmented portions, the method can detect synthetic material in one portion that differs from the natural portion, thereby identifying doublets that would pass conventional screening.
Solution Approach 2:
The method applies different detection approaches to different parts of the gemstone. The crown and pavilion are independently characterized using UV irradiation and luminescence capture, allowing local detection of synthetic material properties that differ from natural diamond properties in specific regions.
2Productivity
If conventional screening methods are used, then processing time is reduced, but detection capability for doublets is insufficient
Solution Approach 1:
The method uses pulsed UV irradiation with specific time windows for capturing luminescence. By applying periodic irradiation pulses and capturing emissions at specific intervals, the method efficiently processes gemstones while maintaining high detection capability for synthetic material through time-resolved luminescence analysis.
Solution Approach 2:
The method introduces an intermediary comparison process between the luminescence properties of the crown and pavilion portions. This intermediary comparison acts as an additional detection layer that maintains productivity while significantly improving the difficulty of undetected doublets, as synthetic material will show mismatched properties.
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
Enables accurate identification of doublet gemstones by matching or mismatching luminescence properties between the crown and pavilion, effectively distinguishing between natural and synthetic components.
Implementation Method 1
irradiating an upper portion and a lower portion of the gemstone with one or more pulses of ultraviolet radiation at a wavelength of substantially 225 nm or less; capturing luminescence emitted by the upper portion of the gemstone and luminescence emitted by the lower portion
Implementation Method 2
One of the one or more time windows may start immediately after an end of the or each pulse and closes between about 50 and 100 ms later, optionally 80 ms later, so that the luminescence comprises phosphorescence
Data Source
AI summary
A method of characterising a composition of a gemstone comprises irradiating an upper portion and a lower portion of the gemstone with one or more pulses of ultraviolet radiation at a wavelength of substantially 225 nm or less; capturing luminescence emitted by the upper portion of the gemstone and luminescence emitted by the lower portion of the gemstone in one or more time windows having a predetermined relationship with the or each pulse; and comparing properties of the captured luminescence from the upper and lower portions. A composition of the gemstone is characterised, based upon the comparison.