The operation of Colombian emeralds has been, since long time ago, one of the main lines of export, due to the high quality and b eauty of Colombian stones. In this work we presented a method of rock analysis, fdetermination of the presence of the beryl, group to which belongs emera lds. An analysis by means of the X-ray diffraction was realized, for 15 powder sextracted from the Colombian region of emerald mines.