Giovanni Ferraris and Stefano Merlino are two outstanding Italian researchers in mineralogy and crystallography. This issue of European Journal of Mineralogy is dedicated to both of them for their pioneering and relevant contributions to modular mineralogy and crystallography. Besides being colleagues for more than four decades as University professors (Giovanni at the University of Torino, Stefano at the University of Pisa), they are close friends as well. This issue celebrates their 80th birthday, as Giovanni (b. 1937) and Stefano (b. 1938) are almost the same age.
Their careers developed in similar ways: Giovanni graduated in Physics in 1960 and became full professor in 1975; Stefano graduated in Chemistry in 1962 and became full professor in 1975.
They were teachers and mentors of a number of Italian researchers in mineralogy and crystallography, and in fact acted as beacons for their skill and their scientific rigour. Their scientific interests are broad and can be summarized under the comprehensive topic of crystal-chemistry of minerals and inorganic compounds, with special attention to order-disorder phenomena such as polytypism, polysomatism, modularity, and twinning. They are authors of hundreds of research articles in peer-reviewed international journals, editors of special volumes like “Modular Aspects of Minerals” (S. Merlino, ed., 1997, vol. 1 of EMU Notes in Mineralogy) and “Micro- and Mesoporous Mineral Phases” (G. Ferraris & S. Merlino, eds., 2005, vol. 57 of Reviews in Mineralogy and Geochemistry). Moreover, they co-authored, together with Emil Makovicky, a reference book on “Crystallography of Modular Materials” (Oxford Univ. Press 2004; paperback edition 2008).
They had important organizational roles in national societies: Stefano was vice-president (1990–1991) of SIMP, and Giovanni was president (1994–1996) of AIC (Associazione Italiana di Cristallografia). Among other prizes, both were awarded the “Plinius” medal, the highest prize granted by SIMP.
Stefano is a fellow of the Mineralogical Society of America; Giovanni is a fellow of the Accademia delle Scienze di Torino; both are foreign members of the Russian Academy of Natural Sciences, honorary members of the Russian Mineralogical Society, and fellows of the Accademia Nazionale dei Lincei.
Both were among those who promoted the merging of the national journals of DMG, SFMC and SIMP into a single international journal – the one you are reading now – with the cooperation of the European Mineralogical Union (EMU). In fact, it was during the first years of EJM, which started in 1989, that they also had important international roles: Giovanni was President of EMU (1992–1996), and Stefano was vice-president (1990–1994) and then president (1994–1998) of IMA.
The recognition of the guiding roles of Giovanni and Stefano, still active after their retirement, is demonstrated by the success of the present special issue, the proposal for which was immediately and enthusiastically accepted by managing editor Christian Chopin; the call for papers quickly resulted in twenty papers from all over the world. This issue has been carefully edited by Luca Bindi and Dmitry Yu. Pushcharovsky, together with Sergey V. Krivovichev. We wish to express our sincere thanks to them and to all authors, as well as the reviewers, for their contribution in the production of this homage to the lifetime commitment towards mineralogy by Giovanni and Stefano (Fig. 1).