The peak positions and relative intensities of the experimental and reference data are an excellent match. There are no peaks that are unaccounted for in either the experimental or the reference data.

This confirms that the most likely impurity, lime, CaO, is absent.

In a new sample the peak at 37.2° is unaccounted for. This implies that the hydroxyapaptite is impure.

The extra peak is consistent with CaO. CaO has another peak at 32.3° but this overlaps with a HA peak. The data imply that CaO is the impurity but strictly 3 or more peaks are required for unambiguous phase identification