AMPHIBOLE OF THE NYBOITE SERIES
There are results of the nomenclature analysis of published data and author's researches of the nyböite series amphiboles. 5 names of these minerals are given in the MMA glossary (Mineral Species 2008), but only two of them have status of the existing end-members: nyböite and fluoronyböite. For others it is specified, that they are «not yet found in nature». The article has the task to prove the natural existence of six end-members of the nyböite series. Four of them are normative (the full series): nyböite, ferronyböite, ferric-nyböite and ferric-ferronyböite. Two others are analogues of the normative ones (in status of the competent mineral species): the first - with dominant potassium - potassic-ferric-nyböite; the second - with dominant fluorine - fluoronyböite. The discussed total number of possible members of the series makes not less than 16 (4 -normative ones, and 12 analogues). By features of their structure, amphiboles of the nyböite series were divided into two separate groups, each one connected with the certain type of geological formations. The first group is characterized by the high predominance of Al over Fe<sup>3+</sup> among M-type cations in C-position (nyböite and ferronyböite), it is connected with the highly baric complexes. The second group distinguishes itself by the sharp prevalence of Fe<sup>3+</sup> above Al among M-type cations in the <i>C</i>-position (ferric-nyböite and ferric-ferronyböite), and it is connected with alkaline complexes. Original data of microprobe analysis and the Mössbauer study of ferric-nyböite from alkaline complex of the Vishnevy Gory mountains, in the Urals, and their high correspondence, are displayed in the paper.