IMA–CNMNC approved mineral symbols

Abstract

Several text symbol lists for common rock-forming minerals have been published over the last 40 years, but no internationally agreed standard has yet been established. This contribution presents the first International Mineralogical Association (IMA) Commission on New Minerals, Nomenclature and Classification (CNMNC) approved collection of 5744 mineral name abbreviations by combining four methods of nomenclature based on the Kretz symbol approach. The collection incorporates 991 previously defined abbreviations for mineral groups and species and presents a further 4753 new symbols that cover all currently listed IMA minerals. Adopting IMA–CNMNC approved symbols is considered a necessary step in standardising abbreviations by employing a system compatible with that used for symbolising the chemical elements.

Introduction

Using text symbols for abbreviating the scientific names of the chemical elements listed on the periodic table is a well-accepted praxis in chemistry, first introduced by the Swedish scientist Jöns Jakob Berzelius (Berzelius, 1814). He used one or two letters selected from the Latin names to convey the elements in a short and concise notation that has been accepted universally since the mid-19^th Century. A system for abbreviating rock-forming minerals was first proposed by Kretz (1983): traditionally known as Kretz symbols. In a similar way to Berzelius, Kretz used a capitalised letter taken from the initial of the name and one or two lower case letters selected from the rest of the word. The selection was chosen to be representative and did not conflict with the element symbols. As the individual letters were not specific to any particular name components, this approach provided flexibility and choice in the selection of new abbreviations used to cover the expanding number of recognised mineral species. Introducing three-letter symbols also had the benefit of being able to generate a maximum of 17,576 combinations of the alphabet (26 × 26 × 26) and therefore offered significantly more diversity than the limited 676 combinations of two-letter abbreviations. Due to the combined function of mineral text symbols as abbreviations, these terms are used interchangeably

Over the years, the list of Kretz (1983) with its 192 symbols was expanded to 240 by Siivolam and Schmid (2007) and to 371 by Whitney and Evans (2010). More recently, Warr (2020) added a further 168 new abbreviations for clay minerals and associated phases. In its guide to authors, The Canadian Mineralogist (2019) also presents a complementary list of 821 Kretz symbols, although these are not entirely compatible with the more widely used collection proposed by Whitney and Evans (2010). Despite the availability of recommended abbreviations for the commonly studied mineral species, to date < 18% of mineral names recognised by the International Mineralogical Association (IMA) have been attributed with a symbol. Also, proposed symbols are not always consistently applied and some authors still prefer to make up their abbreviations rather than to follow published recommendations. This is particularly the case for the remaining ca. 82% of minerals that have not yet been allocated a symbol.

This contribution presents the first complete collection of mineral symbols for all currently listed IMA mineral species and commonly used group names by modifying the Kretz symbol approach (Table 1). The compilation, approved by the Commission on New Minerals, Nomenclature and Classification (CNMNC) (Miyawaki et al., 2021), significantly expands the number of available abbreviations and is designed to improve the degree to which mineral symbols are standardised in future publications. The list of 5744 abbreviated mineral names demonstrates that the Kretz system can be successfully adapted to cover the complete catalogue of recognised minerals and to accommodate new approved species. It also provides a more systematic approach to nomenclature than would be achieved by combining past and future lists in an ad hoc approach.

Table 1. List of IMA-CNMNC approved mineral symbols (4753 new and 991 previously defined) *denotes mineral names where abbreviations have been adopted from previous publications. The origin of all symbols are detailed in the Supplementary material.

Nomenclature

As symbols for the commonly studied minerals are already available, most of these, and in particular those proposed by Whitney and Evans (2010), are adopted in the new listing. However, to cover the full catalogue of mineral names, the nomenclature scheme has been modified to generate new symbols by using a combination of the following four methods (Warr, 2020).

1. (1) The initial letters of a mineral name. These are occasionally used in singular form (e.g. aluminite = A) or as two letters (e.g. chaoite = Ch). The most common are the first three letters of a name (e.g. cyanotrichite = Cya), which provides the best compromise between having a relatively short symbol and having enough letters to give away the character of the name. There are also some rare instances of using the first four letters of a name, but only when shorter options are not available (e.g. mitscherlichite = Mits). This category of abbreviations make up 28% of the listing.

2. (2) A combination of two to four letters considered characteristic of the mineral name. At least two of the letters of this type of symbol are usually clustered together to highlight a characteristic section of the name that aids its recognition (e.g. ewingite = Ewg or neighborite = Nbo). These types of abbreviation make up 32% of the database.

3. (3) A selection of two to four letters expressing components of the name. These represent the initial letter of a name component in terms of how the word is pronounced (e.g. hellandite = Hld) or as the initial letter of a selected syllable in the word (e.g. adranosite = Arn). This type of symbol makes up 28% of the collection.

4. (4) Four or more lettered abbreviations when prefixes are present (e.g. ferro-, ferri, and magnesio-). These are used when related mineral symbols have been previously defined and the letters are selected to preserve consistency between the mineral abbreviations. (e.g. chlorocalcite = Ccal, or monohydrocalcite = Mhcal, where calcite = Cal). Longer abbreviations are also selected if short ones are no longer available. (e.g. natrozippeite = Nzip and nickelzippeite = Nizip, where zippeite = Zip). This symbol type comprises ca. 12% of the database.

A collection of symbols was compiled by first listing published mineral abbreviations from recognised contributions. In the case of conflicting symbols used for the same mineral, for example, Qtz (Kretz, 1983) or Qz (Whitney and Evans, 2010) for quartz, those proposed by Whitney and Evans (2010) were prioritised. Some departure from this published study was, however, introduced to remove symbols that correspond to elements. In this context, Po, Fl, Mc and Ts have been replaced (using method 2) with the Kretz symbols of Pyh, Flr, Mcc and Tsr for the minerals pyrrhotite, fluorite, microcline and tschermakite, respectively. Other departures from the Whitney and Evans (2010) listing are abbreviations that require prefixes following method (4) so that these abbreviations (12 in total) are consistent with existing mineral symbols (e.g. ferro-actinolite = Fact, whereby by actinolite = Act). This modification was also required to generate a sufficient number of abbreviations for the complete collection of minerals that cannot be covered by using two- and three-letter symbols alone. Despite these differences, the symbols are 93% compatible with Kretz (1983), 87% with Siivolam and Schmid (2007), 97% with Whitney and Evans (2010), 75% with The Canadian Mineralogist (2019) listings and 100% with Warr (2020).

To add further diversity and character to new symbols, language-related lettering from the original mineral names was introduced (e.g. löllingite = lö and švenekite = Švn). It is assumed that suitable multilingual text software is now standard to both authors and journals, which may not have been the case in the past. Abbreviations were also selected to reflect their origin, such as people's names (e.g. earlshannonite (Earl Shannon) = Esn) or place names (e.g. clearcreekite = Cck) to which the minerals are dedicated. The symbols for specific mineral species containing elemental information are listed in full (e.g. anzaite-(Ce) = Anz-Ce or allanite-(Ce) = Aln-Ce. In the absence of such element information, the mineral symbol can be used in its less specific form (e.g. anzaite = Anz or allanite = Aln). In the case of mineral phases requiring extensive elemental information for species description, which can lead to long notations, (e.g. jahnsite-(CaFeMg = Jah-CaFeMg), such abbreviations can also be used in their shortened version (e.g. jahnsite = Jah) by defining the species in the text on the first occurrence or in the relevant figure or table caption where the symbol is used.

The collection listed in Table 1 includes the 31 elements that occur as native minerals. Although most of Kretz's pre-existing mineral symbols and those by Whitney and Evans (2010) are adopted, all new symbols have been chosen to maximise consistency in the database so that common mineral names are ideally denoted by the same symbols (e.g. pseudosinhalite = Pshl, where P = pseudo, Shl = sinhalite and Hl = halite). Where possible, the same symbols are maintained for reoccurring name components such as cb for carbide in niobocarbide (Ncb) or tantalcarbide (Tcb). Additionally, elemental information was retained in symbols (e.g. bismuth = Bi, bismite = Bis and bismutite = Bit), as long as this did not conflict with the four methods of nomenclature applied and the need to keep abbreviations as short as possible. Symbols were selected to minimise the average length and, as a whole, the longer names are generally attributed with longer abbreviations. The complete library of mineral symbols, which covers all IMA–CNMNC approved species from the May 2021 version of IMA mineral listing (Pasero, 2021), is based on 4 one-lettered symbols, 260 two-lettered symbols, 4205 three-lettered symbols and 1275 four (or more) lettered symbols including specific elemental notations. In addition to the 5703 currently approved species, the library also contains 41 group and subgroup names inherited from the symbols list of Kretz (1983), Whitney and Evans (2010) and Warr (2020). These cover many common mineral names such as feldspar (Fsp), amphibole (Amp), pyroxene (Px), chlorite (Chl) and biotite (Bt).

A more detailed mineral symbol dataset is provided as Supplementary material. This can be used as a search and match tool for locating mineral names and their recommended symbols. Lists of symbols used for common name components are also given at the base of the datasheet sorted by mineral. New mineral abbreviations can be selected using the ‘symbol picker’ from the list of available symbols included in the supplementary material. These are to be submitted for approval to the CNMNC as part of a mineral name proposal. New listings of symbols will appear on the official IMA–CNMNCs website and in related publications such as the IMA-CNMNC newsletter (Mills, 2010).