Multi spectroscopic techniques to analyze natural minerals to determine corundum type of gemstones from Darfur, Sudan

Abstract EN

The main objectives of this study were to know natural minerals contents to classify their typesand determine corundum type.

Energy Dispersive X-ray Fluorescence spectrometry, X-raydiffraction and Energy Dispersive X-ray Spectrometry coupling with Scanning ElectronMicroscope have been utilized to determine the mineralogical and elemental composition of semigemstone samples collected from two different mine locations in Darfur region western Sudan.

Results obtained from spectroscopic analyses indicated that Aluminum Oxide (Al2O3) waspredominated in FDY sample(A) and Silica (SiO2) was main contain in ODS sample(B) as wellas different percentages of some metal oxides including trace and rare earth elements.

Accordingto the outcome of the Energy Dispersive X-ray Fluorescence results the FDY sample ischaracterized as Corundum (Ruby) and while the ODS sample is classified as Quartz(Carnelian).

These characterizations are depended on physical appearance and color that whencompared to the previous data of gemstones in addition to the analyzing results.

The analysisshowed that ruby major revealed composition were Al2O3 (79.

02 %); SiO2 (10.

88%); SO3(4.

96%) Fe2O3 (2.

27%); CaO (1.

06%); TiO2(1.

08%) and quartz majority compositions wereSiO2 (94.

23%); Al2O3 (1.

96%); SO3 (0.

66%) Fe2O3 (2.

10%); CaO (1.

05%); TiO2 (0.

03%).

X-rayDiffraction scanning tests of the samples showed that a vast majority represented bycorundum (93.

3%)and quartz (99.

1%) in FDY and ODS samples respectively as dominantcompound, similarly for more investigation and delicacy Energy Dispersive X-ray Spectrometrycoupling with Scanning Electron Microscope scan analyzing indicated that Alcompounds(Al2O3) were outnumbered Si compound(SiO2) in FDY sample while in ODSsample there was a significant presence of Si contents represented by standard level (SiO2) onthe bases of available facts of the study FDY sample considered to be corundum (ruby) andODS sample as quartz origin.