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Mineral name/formula hybrids.

In recent decades there has been an unfortunate (in this writer's opinion) trend in mineral nomenclature: the hybridizing of mineral names with formulas. The philosophical root of this practice has been the Levinson suffixes. A. A. Levinson's 1966 article ("A system of nomenclature for rare-earth minerals." American Mineralogist, 51, 152-158) introduced the concept that, instead of coming up with a new name in the traditional way for a new chemical analog of an existing mineral, the chemical symbol for the element substituted in the formula could be tacked on with a hyphen to the back end of the original mineral name. He reasoned that, with so many rare-earth elements to choose from, each having relatively little effect on the properties of the mineral (and thus requiring detailed chemical analysis for identification of the species), it would be more convenient to use suffixes to distinguish each rare-earth analog and then use the root name (e.g. monazite) when the dominant REE is not known. The idea appealed to other mineralogists, who then applied it to the naming of non-REE minerals as well.

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But this merger blurred the line between what constitutes a mineral name and a mineral formula. The result has been nomenclatural cross-breeds such as stilbite-Ca, florencite-(Ce), and donnayite-(Y), and real nomenclatural monstrosities such as whiteite-(CaFeMg) and whiteite-(CaMnMg).

Crystallographers have also succumbed to the temptation, resulting in structurally hybridized names with code letters and numbers added at the end, such as ferronigerite-6N6S. Then that approach was hybridized to include both chemical and structural symbols in the same name, e.g. apatite-(CaOH)-M. In fact, many perfectly good names that have long been entrenched in the literature were overturned by Burke (2008, in this journal, with approval of the International Mineralogical Association) in the name of "tidying up," and were given new hybrid names instead.

Convenience notwithstanding, I personally wish that mineralogists would keep in mind what a "name" is and what it is not. Chemical formulas are not names. Structural formulas are not names. Why would one want to rename a perfectly good mineral such as fluorapatite with the new name apatite-(CaF)? How does this help anyone? It's not even shorter. Is it too much work to remember that the species contains some calcium? Is it too much work to remember that there are four other chemically similar species distinguished by various substitutions; must they instead all have to come out together in an alphabetical list, as a memory aid?

Some common sense is finally beginning to creep back in. An IMA committee chaired by Marco Pasero and Anthony Kampf recently published a revision of the nomenclature of minerals in the apatite supergroup (European Journal of Mineralogy). Among other changes, they specify:
  The use of adjectival prefixes for anions is to be preferred instead
  of modified Levinson suffixes; accordingly, six minerals should be
  renamed as follows: apatite-(CaF) to fluorapatite, apatite-(CaOH) to
  hydroxylapatite, apatite-(CaCl) to chlorapatite, ellestadite-(F)
  to fluorellestadite, ellestadite-(OH) to hydroxylellestadite,
  phosphohedyphane-(F) to fluorphospho-hedyphane. For the apatite group
  species these changes restore the names that have been used in
  thousands of scientific papers, treatises and museum catalogues over
  the last 150 years.


Bravo to Drs. Pasero and Kampf, and the other members of the committee: Cristiano Ferraris, Igor Pekov, John Rakovan and Timothy White.

WEW
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Title Annotation:Notes from the Editors
Publication:The Mineralogical Record
Geographic Code:1USA
Date:Jul 1, 2010
Words:559
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