MICRO-PIXE ANALYSIS OF TRACE-ELEMENT CONCENTRATIONS OF NATURAL RUBIESFROM DIFFERENT LOCATIONS IN MYANMAR

The trace element concentrations found in geological samples can shed light on the formation process. In the case of gemstones, which might be of artificial or natural origin, there is also considerable interes t in the development of methods that provide identification of the ori gin of a sample. For rubies, trace element concentrations present in n atural samples were shown previously to be significant indicators of t he region of origin [S.M. Tang et al., Appl. Spectr. 42 (1988) 44, and 43 (1989) 219]. Here we report the results of micro-PIXE analyses of trace element (Ti, V, Cr, Fe, Cu and Ga) concentrations of a large set (n = 130) of natural rough rubies from nine locations in Myanmar (Bur ma). The resulting concentrations are subjected to statistical analysi s. Six of the nine groups form clusters when the data base is evaluate d using tree clustering and principal component analysis. (C) 1997 Els evier Science B.V.