The German Mineralogical Society mourns the loss of Professor Paul Keller, who passed away in Stuttgart on 4 November 2022 after a prolonged illness at the age of 82. With Paul Keller, the DMG has lost a long-standing and active member.

Paul Keller was born in Șarata in eastern Romania, but Stuttgart became his second home. There he studied mineralogy, earned his doctorate, and completed his habilitation. His habilitation thesis (1973), entitled The Crystal Chemistry of Phosphate and Arsenate Minerals with Particular Emphasis on Cation Coordination Polyhedra and Crystal Water, laid the foundation for his subsequent scientific career. For 26 years, until his retirement in 2006, Keller represented the fields of crystallography and crystal chemistry at the University of Stuttgart. His research focused on the genesis and crystal structures of oxide minerals, theoretical crystal chemistry, and the occurrence of minerals and raw materials in pegmatites. During this period, he also curated the University's Mineralogical Collection.

Keller became widely known through his extensive research in Tsumeb, Namibia, and for his contributions to the discovery and characterization of new minerals. Altogether, he was involved in the description of 22 new minerals, including 13 first descriptions from Tsumeb. For 29 years, until 2016, he served as the German representative and voting member of the Commission on New Minerals and Mineral Names (CNMMN) of the International Mineralogical Association (IMA). It is therefore only fitting that a bismuth–iron phosphate mineral discovered in Schneeberg, Saxony, in 1988 was named paulkellerite in his honor.

We will remember him with gratitude.

Birgit Kreher-Hartmann, Jena

More detailed information on the life and scientific achievements of Paul Keller can be found here.