Spring 2004, Volume 40, Issue 1

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X-Ray Fingerprinting Routine for Cut Diamonds
Roland Diehl and Nikolaus Herres

An X-ray topograph of a 0.75 ct round brilliant diamond. X-ray topography is a nondestructive technique that permits the visualization of internal defects in the crystal lattice of a gemstone, especially diamond, which is highly transparent to X-rays. This technique yields a unique “fingerprint” that is not altered by gem cutting or treatments such as irradiation and annealing. Although previously a complicated and time-consuming procedure, this article presents a simplified X-ray topographic routine to fingerprint faceted diamonds. Using the table facet as a point of reference, the sample is crystallographically oriented in a unique and reproducible way in front of the X-ray source so that only one topograph is necessary for fingerprinting. Should the diamond be retrieved after loss or theft, even after recutting or exposure to some forms of treatment, another topograph generated with the same routine could be used to confirm its identity unequivocally.

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