Introduction
Criteria for a new mineral species
　General considerations

『A mineral substance is a naturally occurring solid that has been formed by geological processes, either on earth or in extraterrestrial bodies (Nickel 1995a). A mineral species is a mineral substance with welldefined chemical composition and crystallographic properties, and which merits a unique name. General criteria for defining mineral species are given below. In practice, most mineral species conform to these criteria, but exceptions and borderline cases inevitably arise, and ultimately each proposal to introduce a new mineral species or to change mineral nomenclature must be considered on its own merits.』

　The concept of a mineral species

『A mineral species is defined mainly on the basis of its chemical composition and crystallographic properties, and these must therefore be the key factors in determining whether the creation of a new mineral species and a new mineral name is justified. If a mineral is found whose composition or crystallographic properties (or both) are substantially different from those of any existing mineral species, there is a possibility that it may be a new species. A general guideline for compositional criteria is that at least one structural site in the potential new mineral should be predominantly occupied by a different chemical component than that which occurs in the equivalent site in an existing mineral species.』

　Suibstances formed by human intervention

『Anthropogenic substances, i.e. those made by Man, are not regarded as minerals. However, there are other cases in which human intervention in the creation of a substance is less direct, and the borderline between mineral and non-mineral can be unclear. One such case is the occurrence of new substances that owe their origin, at least in part, to human activities such as mining or quarrying. If such substances are formed purely as a result of the exposure of existing rock or minerals to the atmosphere or to the effects of groundwater, they can generally be accepted as minerals. However, if their occurrence is due, at least in part, to the interaction of existing minerals with substances of non-geological origin such as blasting powder, corroded human artifacts or industrially contaminated water, then such products are not to be regarded as minerals.
Substances formed by combustion are not generally regarded as minerals. A contentious issue is the occurrence of substances in the combustion products of coal mines, waste dumps or peat bogs. The origin of a particular fire is often difficult to determine, and therefore the possibility of human intervention cannot be entirely eliminated, nor can the possibility of human artifacts contributing to the combustion products. It has
therefore been decided that, as a general rule, products of combustion are not to be considered as minerals in the future.
Another contentious issue is whether substances formed by the action of air or water on anthropogenic substances should be regarded as minerals. A wellknown example is that of the Laurium “minerals” formed by the reaction of seawater with ancient metallurgical slags. A potential problem with accepting similar products as minerals in the modern age is that a multitude of unusual substances could be created purposely by exposing exotic Man-made materials to the influence of weathering agents, and it would not be appropriate to give such substances the same status as minerals formed entirely by geological processes. It was therefore decided that substances formed from Man-made materials by geological agents should not be accepted as minerals in the future (Nickel 1995a). However, the exclusion of such substances from the
mineral lexicon does not preclude their description as artificial substances.
Substances that would not be accepted as minerals according to the above criteria, but which have been accepted in the past are not to be automatically discredited as a result of the new rulings, as it is not our intention to roll back the clock but rather to establish guidelines for the future.』

　Biogenic substances 『It is not always possible to draw a sharp distinction between biogenic substances, i.e. those produced by biological processes, and minerals, which are normally produced by geological processes. For instance, it is becoming increasingly clear that many of the processes associated with diagenesis are influenced, to some extent, by bacterial action, and the biosphere is commonly regarded as an integral part of the geochemical cycle. Nevertheless, it is necessary to make a formal distinction so as to prevent a host of purely biological materials being incorporated into the world of minerals. Some biogenic substances, such as hydroxylapatite in teeth, whewellite in urinary calculi or aragonite in the
shells of molluscs, also exist as minerals formed by geochemical processes, and therefore are regarded as valid minerals. However, purely biogenic substances that have no geological counterparts, or whose origin owes essentially nothing to geological processes, are not regarded as minerals.
However, substances formed by the action of geological processes on organic material, such as the chemical compounds crystallized from organic matter in shale or from bat guano, can be accepted as minerals.』

　Amorphos substances
　The matter of size
　Stability under ambient conditions
　Polymorphs
　Polytypes and polytypoids
　Regular interstratifications
　Polysomatic series
　Modulated structures
　Solid-solution series
Requirements for the approval of new minerals
Treatment of a new-mineral proposal
Mineral groups
Changes to existing nomenclature
　General
　Redefinition
　Discreditation
　Revalidation
　Type specimens
　Preparation of a nomenclature proposal
General guidlines for mineral nomenclature
　Choice of a new mineral name
　Rare-earth minerals
　Extended Levinson modifiers
　Adjectival modifiers
　Varietal names
　Nomenclature of mineral groups
　Nomenclature of polytypes, polytypoids and polymorphs
　Nomenclature of nanometric domains
　Nomenclature of variable-fit homologous series
　Prefixes in mineral names
　Hyphens in mineral names
　Mineral names for synthetic substances
Publication of the descriptions of approved minerals
Advice to editors
References
Appendix I. Members of the IMA Commission on New Minerals and Mineral Names
Appendix II. Changes in nomenclature, 1987-1997