Polished fluorapatite crystal surfaces were etched with lactic acid adjusted to pH4 or with ethylenediamine tetra-acetic acid (Edta) and the surfaces examined by scanning electron microscopy. The resultant acid etch patterns or pits were observed to be typical of the hexagonal system, as expected from the crystal structure of fluorapatite; however, the fluorapatite surfaces exposed to Edta at pH7 were relatively unaffected. Several different natural surfaces of fluorapatite were exposed to lactic acid and the comparative dissolution rate for each surface determined by the micro estimate of the dissolved calcium component. Observations indicated similar dissolution rates for the different surfaces examined. A relatively simple technique was employed to compare dissolution rates of human enamel and fluorapatite under static conditions. Sample granules were suspended upon porous glass filter crucibles and weight losses of the granules versus the time of dissolution were recorded for a variety of solutions. Constant rates of dissolution were obtained, fluorapatite exhibiting low values in lactic acid and EDTA solutions compared with high dissolution rates observed for enamel granules in these solutions. The rate of rate loss of enamel granules in 0.15 M Edta is higher than that in 0.25 M lactic acid. Surprisingly, the opposite was observed for fluorapatite granules.