A Preliminary SIMS Study Using Carbon Isotopes to Separate Natural from Synthetic Diamonds

Abstract

This preliminary study focuses on using secondary ion mass spectrometry (SIMS) to measure relative carbon isotope ratios for natural and synthetic diamonds (i.e. those grown by both chemical vapour deposition [CVD] and high-pressure, high-temperature [HPHT] techniques). The synthetic diamonds (of both CVD and HPHT origin) had significantly lower relative carbon isotope values than the natural diamonds. The lowest value was obtained for the CVD synthetic diamond sample, in agreement with results from other investigators. More research is desirable on the carbon isotope variation of synthetic diamonds.

Hydrogen and Oxygen Stable Isotope Ratios of Dolomite-Related Nephrite: Relevance for its Geographic Origin and Geological Significance

“…A mass spectrometer is needed to determine the isotope ratio values (see box B). The spot produced by secondary ion mass spectrometry (SIMS), laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS), and laser ablation inductively coupled plasma time-of-flight mass spectrometry (LA-ICP-TOF-MS) for stable isotope analysis of gemstones can be restricted to craters of 10-100 μm in diameter and a few angstroms to microns deep (Giuliani et al, 2000(Giuliani et al, , 2005Abduriyim and Kitawaki, 2006;Wang et al, 2016Wang et al, , 2018. The craters produced are very small, to the point of not being noticeable without magnification.…”