An X-ray powder method for the estimation of (K, Ba) feldspars

P. Gay
1965 Mineralogical Magazine and Journal of the Mineralogical Society  
Examination of previous physical methods of estimating the barium-content of these feldspars showed that they are generally unsatisfactory. A new variation diagram is constructed correlating BaO content and values of d 132 determined from diffractometer records. It is estimated that the BaO content of these feldspars can normally be determined to about 2–3% by using this diagram. Some of the problems of the mineralogy of the series are reviewed in the light of the experimental results, in
more » ... l results, in particular the effect of polymorphic changes on the variation diagram. Some experimental evidence of the effect of different structural states upon the value of d 132 is obtained, and the limitations imposed upon the method by the existence of such states are discussed.
doi:10.1180/minmag.1965.034.268.16 fatcat:4hx2rzqozzdmxfj5fphgzm34ea