The IMA-CNMNC dominant-constituent rule revisited and extended

F. Hatert, E.A.J. Burke

    Research output: Contribution to JournalArticleAcademicpeer-review


    Mineralogical nomenclature in solid-solution series follows a system that has been called the 50% rule, more correctly the 100%/n rule or the dominant-constituent rule, in which the constituents are atoms (cations or anions), molecular groups, or vacancies. Recently developed systems of nomenclature for the arrojadite and epidote groups have shown that a group of atoms with the same valency state must also be considered as a single constituent to avoid the creation of impossible end-member formulae. The extension with this dominant-valency rule is imposed by all cases of coupled heterovalent-homovalent substitutions. End members with a valency-imposed double site-occupancy may result from single-site heterovalent substitutions and from coupled heterovalent substitutions at two sites where there is a disparity in the number of these two sites.
    Original languageEnglish
    Pages (from-to)717-728
    JournalThe Canadian Mineralogist
    Publication statusPublished - 2008


    Dive into the research topics of 'The IMA-CNMNC dominant-constituent rule revisited and extended'. Together they form a unique fingerprint.

    Cite this