2 3 4 Pliniusite, Ca5(VO4)3F, a new apatite-group mineral and the novel natural ternary solid- 5 solution system pliniusite–svabite–fluorapatite 6 7 Igor V. Pekov1*, Natalia N. Koshlyakova1, Natalia V. Zubkova1, Arkadiusz Krzątała2, Dmitry I. 8 Belakovskiy3, Irina O. Galuskina2, Evgeny V. Galuskin2, Sergey N. Britvin4, Evgeny G. 9 Sidorov5†, Yevgeny Vapnik6 and Dmitry Yu. Pushcharovsky1 10 11 1Faculty of Geology, Moscow State University, Vorobievy Gory, 119991 Moscow, Russia 12 2Institute of Earth Sciences, Faculty of Natural Sciences, University of Silesia, Będzińska 60, 13 41-200 Sosnowiec, Poland 14 3Fersman Mineralogical Museum of the Russian Academy of Sciences, Leninsky Prospekt 18-2, 15 119071 Moscow, Russia 16 4Department of Crystallography, St. Petersburg State University, University Emb. 7/9, 199034 St. 17 Petersburg, Russia 18 5Institute of Volcanology and Seismology, Far Eastern Branch of Russian Academy of Sciences, 19 Piip Boulevard 9, 683006 Petropavlovsk-Kamchatsky, Russia 20 6Department of Geological and Environmental Sciences, Ben-Gurion University of the Negev, POB 21 653, Beer-Sheva 84105, Israel 22 23 † Deceased 20 March 2021 24 25 *Corresponding author:
[email protected] 26 2 28 ABSTRACT 29 The new apatite-group mineral pliniusite, ideally Ca5(VO4)3F, was found in fumarole deposits at the 30 Tolbachik volcano (Kamchatka, Russia) and in a pyrometamorphic rock of the Hatrurim Complex 31 (Israel). Pliniusite, together with fluorapatite and svabite, forms a novel and almost continuous 32 ternary solid-solution system characterized by wide variations of T5+ = P, As and V. In paleo- 33 fumarolic deposits at Mountain 1004 (Tolbachik), members of this system, including the holotype 34 pliniusite, are associated with hematite, tenorite, diopside, andradite, kainotropite, baryte and 35 supergene volborthite, brochantite, gypsum and opal.