Suzuki phase precipitates1 produced by divalent impurities in alkali halide crystals can act as preferential gucleation sites for vapor deposited metals using the gold decoration method2. The present work applies this technique to the study of NaCl: FeCl2. Crystals with several FeCl2 concentrations were grown by the Kyropoulos method in a controlled atmosphere and thermally homogenized. The final impurity concentration Cs was determined by atomic absorption spectroscopy. Precipitates were inducel bg linear cooling from 550°C to room temperature at rates of 7.64, 3.82, and 23°C/hr. Gold decoration was performed at 10 Torr on vacuum-cleaved surfaces at 100°C. Precipitates were visible because of an enhanced nucleation density: Figs. la - c. The volume fraction Vσ of precipitates was determined from the total fractional area of the precipitates in micrographs taken from several areas of the replicas. Vσ is linearly related to Cs (Fig. 2) with a slope of 8.1 ± 1.0.