Ferrites are offered in a wide variety of material grades and geometries to suit different applications. Often, a particular geometry may be offered in multiple material grades. In order to find a suitable replacement; Sometimes it is necessary to evaluate a ferrite core to determine what type of material it was made out of. There are many distinguishing characteristics separating different ferrite material grades but, the main material characteristic is initial permeability. This paper explains how to evaluate a core for initial permeability along with a simplistic surface resistance test. These two characteristics can give a good estimation for the material grade and type of a ferrite.