A pyralspite garnet from an anomalously magnetic concentrate ofa pegmatitic cassiterite ore has been investigated using 57Fe nuclear gammaray resonance spectroscopy. The quadrupole splitting and isomer shift values of 3.6 mm/s and 1.4 ram/s, respectively, are among the largest observed for Fe z+ ions and indicate a very low covalency of the dodecahedral Fe 1+-O 2bonds. These data support the more recent and lower value (10.2-10.1 kcal/ mole) of White and Moore (1972) for the CFSE of the dodecahedral Fe z+ ion and suggest that the CFSE should be a useful approximation to the site preference energy of Fe 2 § for this site.