Olivine composition determination with small-diameter X-ray powder cameras

Abstract

Summary Olivine composition can be rapidly and accurately obtained by using standard (Straumanis-mounting) 57·3 mm X-ray powder cameras. A determinative curve based on analysed natural olivines has been constructed by plotting the mol. % Fo against the spacing of back-reflection line 174. The regression equation for the composition range Fo 100 to Fo 30 is Fo (mol. %) = 4151·46−3976·45 d 174 using Fe- Kα 1 radiation. The fayalite end (Fo 30 to Fo 0 ) of the determinative curve shows a relatively sharp break from a straight-line relationship of d -spacing versus composition. Practical applications of the determinative curve are briefly presented.