A gamma-spectrometric method independent of radon escape for the determination of U and Ra in rock samples based on the 63
keV and 1001 keV as well as 185 keV lines is described and discussed. A simple experimental procedure is given for the determination
of the self-absorption factor. The method has been applied for the determination of uranium and radium in rock samples from
Morocco containing uranium between 17.5 wt.% and 0.026 wt.%. The limits of determination, at 95% confidence level and 10%
standard deviation, for the 63 keV and 1001 keV lines were found to be 0.075 wt.% and 0.62 wt.%, respectively, using samples
of 6 g and chosing 1 h measuring time.