The use of diacritical marks in mineral names has been the subject of several proposals to the CNMMN, lastly in 1999 by the former member for New Zealand, Douglas Coombs.
In both cases these names were approved by the CNMMN with their diacritical marks, and they should consequently be used as such.
*G (Grandfathered) = names considered to represent valid species described before 1959; Q (Questionable) = names published before 1959 and considered not to represent valid species; N (Non-approved) = names published after 1959 without CNMMN approval.
The activities of the CNMMN, and its various recommendations for mineral nomenclature have been widely published in a substantial number of mineralogical journals over a number of years, and there is a clear need to consolidate these reports to provide an up-to-date report on the procedures currently followed by the CNMMN and to provide updated guidelines on mineral nomenclature.
It must be understood that the CNMMN does not wish to impose an arbitrary set of rigid rules on the mineralogical community, but rather to provide a set of coherent guidelines that provide a reasonably consistent approach to the introduction of new minerals and the application of mineral nomenclature.
However, in the past some amorphous substances (e.g., georgeite, calciouranoite) have been accepted as mineral species by the CNMMN.
However, many of the species in the list have not been characterized formally, nor have they been submitted for approval to the CNMMN.
On the other hand, although fluorocannilloite exists the hydroxyl-dominant analogue is not yet known; if it is found and approved by the CNMMN, it would receive the name cannilloite.
The species whose names are given in bold type are the equivalents of species that are known to have been formally approved or "grandfathered" by the CNMMN. Most of these were recognized in the Glossary of Mineral Species 1995.
The definition does not conform rigidly with the definition given by the CNMMN
and quoted by Fleischer and Mandarino (1995): "Polytypes have been defined as substances that occur in several different structural modifications, each of which may be regarded as built up by the stacking of layers of (nearly) identical structure and composition, and with the modifications differing only in their stacking sequence." Each polytype of a species is denoted by adding a suffix to the species name.
Although the main purpose of this definition is to provide internal guidelines for the work of the CNMMN, it is hoped that it will be also generally accepted by mineralogists and other earth scientists.
The CNMMN has therefore ruled that, in the future, chemical compounds formed by the action of geological processes on anthropogenic substances cannot be considered as minerals.