| Abstract
| - The potentialities of laser ablation coupled to ion cyclotron resonance Fourier transform mass spectrometry areevaluated to distinguish natural and artificial opals. Thedetection of specific species in both ion detection modesleads us to obtain relevant criteria of differentiation. Inpositive ions, species including hafnium and large amountsof zirconium atoms are found to be specific for artificialopal. In contrast, aluminum, titanium, iron, and rubidiumare systematically detected in the study of natural opals.Moreover, some ions allow us to distinguish betweennatural opal from Australia and from Mexico. Australiangemstone includes specifically strontium, cesium, andbarium. Moreover, it is also found that the yield of(H2O)0-1(SiO2)nX- (X- = O-, OH-, KO-, NaO-, SiO2-,AlO1-2-, FeO2-, ZrO2-, and ZrO3-) and (Al2O3)(SiO2)nAlO2- ions depends on the composition of the samplewhen opals are laser ablated. Ions, which include zirconium oxide species, are characteristics of artificial gem.In contrast, natural opals lead us, after laser ablation, tothe production of ions including H2O, Al2O3 motifs andAlO-, KO-, NaO-, and FeO2- species.
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