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Published December 2017 | public
Journal Article

Accurate Reporting of Key Trace Elements in Ruby and Sapphire Using Matrix-Matched Standards

Abstract

To improve the accuracy and efficiency of trace element analysis in ruby and sapphire, standards sets containing matrix-matched corundum with targeted levels of beryllium, magnesium, silicon, titanium, vanadium, chromium, iron, and gallium were created. Ultra-high-purity corundum was also incorporated as a "true matrix zero." To our knowledge, these sets contain the most accurate standards for the key trace elements in corundum today. The standards were designed to cover the optimal range of the main trace elements typically characterized in natural ruby and sapphire. Additionally, we were able to accurately quantify silicon in corundum by successfully resolving the ^(28)Si^+ peak from the ^(27)Al^1H^+ peak using the superior mass resolving power of secondary ion mass spectrometry (SIMS) as compared to laser ablation–inductively coupled plasma–quadrupole mass spectrometry (LA-ICP-QMS).

Additional Information

© 2017 Gemological Institute of America. This work would not have been possible without the support of many individuals. Discussions with Prof. George Rossman at Caltech were invaluable during the course of the project. Discussions with Dr. Chandra Khattak regarding the high-purity material were very much appreciated. To help verify our data at various stages, discussions with Dr. Lyudmila Goncharova of the physics and astronomy department at the University of Western Ontario, Dr. Hassaram Bakhru at the State University of New York, Albany, and Dr. Tim West at Evans Analytical Group were most helpful. We recently worked with Professor Graham Pearson's lab on the issue of using sector field ICP-MS technology with 193 nm LA to accurately quantify low levels of silicon in corundum. Some preliminary work with Dr. Mandy Krebs and Dr. Yan Luo from Prof. Pearson's lab is underway, and results will be included in a future publication. Discussions with Dr. Karl Schmetzer regarding quantification of silicon in corundum were very much appreciated. We would like to thank Troy Ardon for creating "AtomicDensityCalculator" software for future SIMS data processing. Finally, the support of GIA management (Tom Moses and Shane McClure) was essential to see this project to the end.

Additional details

Created:
August 19, 2023
Modified:
October 18, 2023