Conductive methods of measuring electrical conductivity are unsatisfactory for testing diamond drill core specimens of metallic ores. An inductive method which avoids many of the inherent difficulties of the conductive methods is described. The method consists of measuring the change of impedance of solenoid when a core specimen is inserted in it. A correlation between the change of impedance of the solenoid and the physical properties and dimensions of a spherical core is achieved mathematically. This result is extended, empirically, to include cylindrical cores. A convenient way to make the required measurements is outlined, followed by a description of the design of a particular inductive conductivity meter. Sample results obtained with this instrument are presented, and one application of the method is mentioned.