A tool for drilling subterranean formations includes a tool body having a face surface, a blade extending radially outward on the face surface toward a gage surface, and a plurality of cutting structures disposed in the blade. Each of the plurality of cutting structures comprises a substantially spherical body of particulate impregnated matrix material. A method of forming the tool includes forming a tool body having the plurality of cutting structures dispersed therein. A method of using the tool includes rotating the earth-boring tool within a wellbore and engaging a formation material of an earth formation with an outer surface of the blade and wearing the outer surface of the blade to expose the spherical cutting structure. After wearing the outer surface of the blade, the method includes engaging the earth formation with the spherical cutting structure.