Identification of Rubies by Energy-Dispersive X-Ray Fluorescence Spectrometry

Abstract

Ruby, the red variety of the mineral corundum, is among the most valuable of gems. Ruby is allochromatic, with the color arising from the trace concentrations of chromium (Cr). Gemmologists face two problems in the identification of rubies. The first is the determination of whether a ruby is natural or synthetic; synthetic rubies are much less valuable but may not be distinguishable from natural rubies with the use of conventional tests (e.g., hardness, density, and refractive index). The second is the determination of the source of origin.