Resumen de Guidelines for the identification of anhydrous Mg/Ca carbonates
The interpretation of X-ray diffractograms of anhydrous Mg/Ca carbonates is not always unequivocal. A number of examples are given in order to illustrate this point. On the basis of the publications discussed, guidelines for the identification of anhydrous Mg/Ca carbonates are being presented. In the first place, measurement of the X-ray diffractogram at least from 25° to 55° two theta (when using Cu-K[alpha] radiation) will be needed. In the second place, an adequate subdivision of the x-axis of the diffractogram is required, so that accurate readings of the two theta values are made possible. In the third place, all of the diffraction peaks, or at least as many as possible, should be recognizable in the diffractogram. Identification of a specific mineral on the basis of only its main peak will not lead to an adequate interpretation. In the fourth place, the amount of crystalline substance should be sufficient to allow for clear and unambiguous X-ray diffractograms. In the fifth place, identification of anhydrous Mg/Ca carbonates in mixtures should involve the determination of all other minerals present. Instead of using mixtures in X-ray diffraction, attempts should be made to make the sample monomineralic by way of separation techniques. Finally, great care should be devoted to the correct interpretation of the diffraction peaks present in the recorded signal.
