Hallo All, We are using Rietveld refinement for quantitative phase analysis. I would like to know just how "quantitative" it really is, on an absolute as well as a relative basis. The sample is obviously a large source of error. Does anybody know what relative errors one can expect, or can someone supply me with a suitable reference? Thank you very much in advance. Regards, Johannes Johannes J. Retief Sasol Technology (Pty) Ltd P. O. Box 1 1947 SASOLBURG South Africa Tel. : +27 16 960-2940 Fax : +27 19 960-2826 e-mail: [EMAIL PROTECTED] [All views expressed are my own and not necessarily that of my employer.]