It is with profound sorrow that we announce the passing of Dr. Mati Raudsepp, one of the stalwarts of Canadian mineralogy, on 10 January, 2024 after an extended illness. Dr. Raudsepp had retired to Guelph, ON, after serving as the Director of the Electron beam/X-ray Diffraction facility and as an Honorary Professor in the Department of Earth and Ocean Sciences at the University of British Columbia for nearly 25 years.
Dr. Raudsepp grew up in Hamilton, ON and obtained a BSc from McMaster University (1971), along with a MSc (1979) and PhD from the University of Manitoba (1984). His PhD focused on the characterization of the bulk composition and structural state (cation order) in synthetic amphiboles using a combination of an SEM examination of run products (before it was the norm) and refinement of PXRD data via the Rietveld method. The latter was of high interest to Dr. Raudsepp and it underpinned his research program throughout his career.
As a researcher, Dr. Raudsepp was an applied mineralogist, who sought to resolve geological problems by using the chemistry, spectroscopy and crystal-structure refinements of the most basic components of the rocks, the minerals themselves. In the 1970’s, he worked both in the field and office for the Ontario Geological Survey in northwestern Ontario with skilled geoscientists such as Dr. Phil Thurston and Mr. Lorne Ayers and for the Geological Survey of Canada. These experiences honed his skills in combining field-based observations with those made in the lab, as well as instilling a love of flight (DeHavilland Beavers were his favourite). In the early part of his research career, he focused on the phosphates and oxides found in rare-element pegmatites. After fruitful interactions with Dr. John J. Jambor, Dr. Raudsepp worked on developing rapid, precise techniques suitable for the determination of the modal mineralogy and compositional variations in mine tailings, an avenue of research that continues with those trained under his guidance. A geologist at heart, the skill set that Dr. Raudsepp had developed over his career allowed him to seamlessly contribute to material science research (including work on high T semiconductors), leading to collaborations with those working in the mining industry, along with chemists and engineers. He demonstrated a profound interest in interdisciplinary research that allowed him to make meaningful contributions to the development of new materials and new approaches to studying mining-related wastes, but also in working in the other direction, in the characterization of new minerals having synthetic analogues. Dr. Raudsepp was well published, with 69 papers, 3230 citations and > 13,000 reads. For many of us, these numbers fall far short of the true impact he had on our research programs and careers.
In addition to his commitment to research and mentorship, Dr. Raudsepp served the Mineralogical Association of Canada (MAC) in several ways. Most notably, he was Treasurer from 1996-2006, leading the MAC in developing fiscally responsible approaches that would serve the MAC well over the long term. He also served as an Associate Editor for The Canadian Mineralogist (now the Canadian Journal of Mineralogy and Petrology) over the period 2002-2005. Dr. Raudsepp also played a key role in running the first Berry Summer school, this appropriately dedicated to powder X-ray diffraction techniques. In recognition of his long-term commitment to the MAC, Dr. Raudsepp was awarded the Leonard G. Berry medal in 2006.
Mati was born 27 March 1947 in Göteborg, Sweden, to Pauline and Arnold Raudsepp (predeceased), who had escaped their home in Tallinn, Estonia, just hours before Soviet soldiers began their occupation in September, 1944. The family immigrated to Canada (via Halifax) in 1951 and settled in Hamilton, ON. Mati was a proud Estonian-Canadian who contributed to ensuring traditions remained vibrant on this side of the Atlantic. He was meticulous, with an incredible eye for detail and a gift for translating his knowledge and observations into solutions related to solid-state or geologically relevant problems. He gave freely and willingly of his time to all those conducting research, regardless of what stage they were at in their careers. He had a wonderful sense of humor and an acerbic sense of wit; his ability to tell a good story was second to none.
We are all a bit poorer with the loss of Dr. Mati Raudsepp, a friend, mentor and professional colleague of many. Our condolences go out to his sister, Evy Beraldo (Guelph, ON) and all his family members.
By Andy McDonald, with contributions from Evy Beraldo, Scott Ercit, Gina Lecheminant and Sasha Wilson.
Selected works of Dr. Mati Raudsepp
Coolbaugh, M.R., McCormack, J.K., Raudsepp, M. & Czech, E. (2020). Andymcdonaldite(Fe3+2Te6+O6), a new ferric iron tellurate with the inverse trirutile structure from the Detroit district, Juab County, Utah. The Canadian Mineralogist 58, 85-9
Paradis, S., Keevil, H. Simadl, G.J. & Raudsepp, M. (2015). Carbonate-hosted nonsulphideZn–Pb mineralization of southern British Columbia, Canada. Mineralium Deposita 50(8).
Wilson, S., Raudsepp, M. & Dipple, G. (2006). Verifying and quantifying carbon fixation in minerals from serpentine-rich mine tailings using the Rietveld method with X-ray powder diffraction data. American Mineralogist 91, 1331-1341.
Peets, D.C., Liang, R., Raudsepp, M. & Hardy, W.N. (2009). Encapsulated Single Crystal Growth and Annealing of the High-Temperature Superconductor Tl-2201. Journal of Crystal Growth 312(2).
Vinals, J., Jambor, J.L. Raudsepp, M. & Roberts, A.C. (2008). Barahonaite-(Al) and barahonaite-(Fe), new Ca-Cu arsenate mineral species, from Murcia Province, southeastern Spain, and Gold Hill, Utah. The Canadian Mineralogist 46, 205-217.
Jambor, J.L., Raudsepp, M. & Mountjoy, K. (2005). Mineralogy of Permeable Reactive Barriers for the Attenuation of Subsurface Contaminants. The Canadian Mineralogist 43, 2117-2140.
Raudsepp, M. & Pani, E. (2002). The crystal structure of cobaltarthurite, Co2+Fe3+2(AsO4)2(OH)2.4H2O: A Rietveld refinement. The Canadian Mineralogist 40, 733-737.
Raudsepp, M., Turnock, A.C. & Hawthorne, F.C. (1991). Amphibole synthesis at low pressure: what grows and what doesn't. European Journal of Mineralogy 3, 983-1004.
Raudsepp, M., Hawthorne, F.C. & Turnock, A.C. (1990): Evaluation of the Rietveld method for the characterization of fine-grained products of mineral synthesis: The diopside-hedenbergite join. The Canadian Mineralogist 28, 93-109.
Ayres, L.D., Raudsepp, M., Averill, S.A. & Edwards, G.R. (1972). Geological compilation series, Favourable Lake-Popular Hill area, Deer Lake sheet, District of Kenora (Patricia Portion). Ontario Geological Survey Publication PO768.