A study to, physically and chemically, characterise the volcanic dust particles, from Mt. Semeru and Mt. Bromo, has been done. All samples were treated and prepared for examination using three different equipment, XRD, FE-SEM, and XRF. The results from analysis using XRF indicated that, both sample clusters have some common chemical atomic/molecular contents, and both are dominated by the Fe and Si traces. However, the results from analysis using other two equipment do not show the same dominance of Fe and Si. XRD results have indirectly indicated the present and dominance of Si and Fe. The main contents of the samples from Mt Semeru were Fe (39.2%), Si (27.9%), and other elements such as Ca (12,7%), Al (12), and K (2,69%). Zinc (Zn) was an element with lowest concentration, (0.03%). Results from the use of XRD, on the samples from Mt. Bromo, indicated the close similarity of their spectral patterns with those of Semeru. Elements, such as Ca, Al and K, exist in the both sample clusters. Comparing the current study, with study of Omar [8], suggested that Si found in the sample Sem1, for instance, has a crystalline structure, with Miller index of [1 1 1], and 2-theta angle of about 28o , while the Fe has crystalline structure, with index of [2 0 0], with 2-theta angle of about 65o . In general, the study using the three kind of equipment for samples from the two mountains, indicate the existence of many metal traces, mostly transition metals, with their various concentrations, i.e., Fe, Na, Ca, Mg, Ti, K, Mn, Cu, V, Cr, Rb, Sr, Ba, Zn, and Pb. Toxic traces such as F was not detected. From FE-SEM study it was revealed, that, the volcanic dust particles, have sizes of order of ten to few hundreds of micrometer
Characterization of moving dust particles
