The death of Academician Professor Ivan Kostov on 31 March 2004 brought to an end the remarkable career of one of Europe’s most distinguished geologists.
Inspired by walking trips as a schoolboy in the Rhodope Mountains of his native Bulgaria he embarked of a lifelong study of geology and mineralogy. After graduating in natural history at Sofia University (1936) he was appointed (1938) as an assistant in the Mineralogical-Petrographical Institute at that university. In 1940 he was granted a scholarship at the Royal School of Mines of Imperial College, London, where he was awarded a DIC (1941) and elected Fellow of the Geological Society (1943).
Although forced to remain in London for the duration of the Second World War he published papers on ore deposits in Mining Magazine. On his return to Bulgaria in 1945 Ivan was elected Associate Professor at the chair of mineralogy and petrography, Sofia University, where he resumed his research. His approach was based on the belief that the conditions of formation of minerals are to be interpreted by detailed examination of the morphology of crystals, their chemical composition and their paragenetic associations. In 1954 he published the principles of a new classification of minerals and in 1962 the principles of his crystallogenetic analysis which makes possible the prediction of the discovery of new minerals, subsequently confirmed by numerous finds throughout the world.
His studies on the chemistry of zeolites led to his interpretation of their sequence of formation. Studies in the Srednagorie zone and the Rhodope Mountains by Ivan and his collaborators confirmed his theoretical conclusions regarding the zonation of zeolites, but in addition established important criteria in the search for lead-zinc and copper deposits. The publication of more than 280 papers, monographs and textbooks bears witness to the breadth of his interests which included the characterisation of minerals and their genesis, crystal morphology, crystal chemistry, geochemistry, systematics of minerals, mineral deposits and metallogeny, incorporating detailed observations on the minerals of igneous and metamorphic pegmatites, hydrothermal ores and their alteration products such as sulphasalts and sulphides, zeolites and rock-forming minerals. He also explored original ideas on paragenetic and crystallo-chemical trends in mineral formation, epitaxic phenomena, symmetry of crystals and crystal aggregates, mineral zonation, and temporal and lateral fractionation of the chemical elements in the Earth’s crust. His last monograph, Crystal habits of minerals, published in 1999 when he was 86 (co-authored with his son Ruslan) combines discussion of modern ideas and concepts with an extremely comprehensive overview of crystal morphological data for the most widespread minerals.
By 1965 recognition of his outstanding contributions to geology was acknowledged by being upgraded to Foreign Member of the Geological Society (the title was later changed to Honorary Fellow) and the following year he was elected a full member of the Bulgarian Academy of Sciences, having been elected as a corresponding member in 1961. The many honours accorded to Ivan both in Bulgaria and internationally are too numerous to be included but particular mention should be made of his outstanding service to the International Mineralogical Association of which he was President (1982–1986).
Ivan is remembered for his exceptional industry, persistence, efficiency and creative ardour which, combined with a modest, helpful, direct and friendly manner provided a perfect example to his students and younger colleagues.
J G MacDonald, with gratitude to Prof. Ivan Bonev for permission to draw on information from an obituary in Mineralogical Magazine, and to J. Minceva-Stefanova for additional information.