Kimberlites are of interest for geologists because they present important sources of diamonds. Electrical methods usually provide useful information to delineate kimberlite pipes, which typically show small apparent resistivity values. However, to the best of our knowledge, nobody studied, why intrusive rock like kimberlite is a good electrical conductor. We carried out multi-salinity experiments with kimberlite sample (autholitic breccia) taken in Arkhangelsk region (Deposit Lomonosova). We saturated sample with 9 brines of different electrical conductivity values (from 0.01 to 2.68 Sm-1), and we measured its complex electrical conductivity with SIP FUSCH III instrument in the frequency range from 1.4 mHz to 20 kHz. At the brine electrical conductivity range below 0.16 Sm-1, we found the real part of the bulk electrical conductivity to be larger than that of the brine. Within the studied brine electrical conductivity range, the quadrature conductivity at 1.46 Hz varies in the range from 3 to 5 mSm-1, which values are larger than that typically obtained for e.g., volcanic rocks and sandstones. We attribute this behavior of the complex conductivity to the surface conductivity occurring within the electrical double layer coating the interface between the solid and liquid phases.