Quiz: Remember the definition of mal de mer?
a carbonate mineral, calcium manganese carbonate [CaMn(CO3)2]. Confirmed as a naturally occurring species in 1955, it was originally found at Kutna Hora, Bohemia; it also occurs in Franklin, N.J., U.S., and Chvaletice, Czech Republic. The manganese analogue of dolomite, it forms a chemical substitution (solid-solution) series with that mineral, in which magnesium replaces manganese in the crystal structure. It is probably intermediate in the discontinuous (at normal temperatures) solid-solution series between calcite (CaCO3) and rhodochrosite (MnCO3). For detailed physical properties, see carbonate mineral (table)