Zdeněk Johan, an outstanding Czech-French mineralogist and a great colleague, passed away in February 2016. He served as Scientific Director of the French Bureau de Recherches Géologiques et Minières (BRGM), became a fellow of professional and learned societies and received numerous honours and distinctions for his scientific achievements in mineralogy, crystal chemistry, petrology and ore geology (see Ettler, 2016). He also served in 1993 as president of the Société française de Minéralogie et de Cristallographie (SFMC), a founding society of the European Journal of Mineralogy (EJM). When asked by the Editorial Board, we thus immediately agreed to organize a special issue of EJM to celebrate Zdeněk Johan’s career.
We were surprised by the feedback we received. We hope that the selection of papers, all following in the footsteps of Zdeněk Johan’s research activities, will resonate in the geoscience community. This special issue starts with Zdeněk’s late publication on the role of fluids in chromitite formation in ophiolite complexes (Johan et al., 2017), followed by an intriguing view on the origin of super-reduced mineral assemblages in ophiolite chromitites by Bill Griffin’s group (Xiong et al., 2017) and two articles on platinum-group minerals in ophiolites (Zaccarini et al., 2017; Augé et al., 2017). Platinum-group minerals occurring in different geological settings have always been a central theme in Zdeněk’s research and are represented here by several articles, which include the description of new minerals, new occurrences and analytical/experimental studies (Vymazalová et al., 2017; Laufek et al., 2017; Barkov et al., 2017; Pašava et al., 2017; Cabri et al., 2017; Makovicky & Karup-Møller, 2017). Following Zdeněk’s early work on sulphosalts, we were happy to attract a series of papers on this mineral group, including descriptions of new minerals and structural studies (Škácha et al., 2017; Sejkora et al., 2017; Bindi & Paar, 2017; Meisser et al., 2017; Topa et al., 2017a and b; Orlandi et al., 2017). The next papers are related to Zdeněk’s other favourite topics: the mineralogy of tin deposits (Breiter et al., 2017; Lerouge et al., 2017), and pegmatites (Novák et al., 2017). This special issue is rounded off with an experimental study on the reactivity of nanocrystalline manganese oxides (Grangeon et al., 2017).
We were proud to serve as guest editors for this issue in memory of Zdeněk and would like to thank more than 40 reviewers, managing editor Christian Chopin and other editors of EJM (Sergey Krivovichev, Pierfranco Lattanzi, Edward Grew), and the staff at the publishing house for their invaluable help.