The first applications of physical chemistry to mineralogy date back to more than a century ago, and extensive use of this discipline is rapidly increasing in mineral sciences. Familiarity with thermodynamics still appears indeed to be more proper of petrology rather than of mineralogy, although the gap between these two fields is shrinking; in other fields, such as for instance spectroscopy, successful application of physical-chemical concepts to minerals is becoming more and more general. As a consequence, new techniques and interesting possibilities continue to appear, including those involving advanced quantum-mechanical calculations.
However, although the situation is very positive as a whole, sometimes the use of rather questionable concepts, data, and summary procedures is luring and appears to be justified in practice because a more correct treatment is too elaborate. The errors deriving from such an indiscriminate choice might be hard to correct in the future, especially if the results (which are strikingly good in some selected cases) are apparently supported in front of possible future users by the full strength of an exact and advanced discipline. For instance, although thermodynamics is by itself an exact science, if too approximate data and theories are used the conclusions are not necessarily exact to exclude the possibility of their violation in practice. On the other hand, these possible failures should not lead to discouraging the use of physical chemistry in the earth sciences, as an unjustified reaction.
In view of the problem outlined above and of the present considerable redundancy of crystallographic data with respect