This contribution sketches important stages of the life and work of Professor Dr Joachim Bohm, together with an abbreviated bibliography that considers only those contributions that immediately relate to these stages. In total, the publication list of Joachim Bohm contains close to 200 entries, covering issues of crystal symmetry, physico-chemical crystallography as well as growth and characterization of single crystals of advanced ceramic materials.This year, the German mineralogist and crystallographer Joachim Bohm celebrated his 80 th birthday at his home in Berlin-Treptow. Professor Bohm was born on March 25, 1935 in Brandenburg (Havel). In 1941, he entered primary school in his hometown, and eventually obtained his university-entrance diploma (Abitur) in 1953. From 1953 to 1958, he studied mineralogy at Humboldt University Berlin under the tutelage of the eminent crystallographer Wilhelm "Will" Kleber, and received the equivalent of a M.Sc. degree with a thesis on etching of dolomite in optically active acids [1]. This work catered to the particular interest of Kleber who already in 1931 had dealt in his Ph.D. thesis at Heidelberg University with etching of single crystals of fluorite [2] and later had published a paper on the mechanism of etching of single crystals with optically active acids [3].Comparing the symmetry of etch pits produced with hydrochloric acid on {1011} of calcite and dolomite, it appears that the pits are monosymmetric with one mirror plane on calcite (crystal class 3m) but asymmetric on dolomite (crystal class3) [4]. However, adding optically active acids such as laevorotatory (l) or dextrorotatory (d) tartaric or amino acids, the etch pits on calcite reveal asymmetry, too. This means, that on faces perpendicular to the symmetry plane, this symmetry element apparently disappears, a phenomenon called hypomorphy. The reason for this is found in the observation, that the asymmetric l-or d-molecules will be adsorbed with different energies on enantiomorphous, that is, stereochemically different L-and D-surfaces. According to Kleber's adsorption theory of etching of single crystals [5], it is then possible to distinguish between enantiomorphous D-faces {1011} and L-faces {0111}, depending on the orientation of the etch pits. Later, these rather erudite studies found their wide-reaching corollary in the controversial hypothesis by Cairns-Smith [6] that selfreplication of exclusively l-molecules on clay crystals in solution might provide a simple intermediate step between biologically inert matter and organic life. At the core of this hypothesis is the assumption of energetically preferred adsorption of left-handed amino acids such as l-alanine, l-valine, and l-norvaline on clay minerals that led to simple proteins such as albumin and globulins.As an inevitable result of these considerations, Joachim Bohm became keenly interested in theoretical crystallographic questions related to group theory, in particular symmetry groups of other-dimensional systems. This included work on the theory of...
