This study is a part of an overall research project on the effects of microwave (MW) irradiation on rocks for assisted rock breaking systems as well as mineral processing at McGill University. For the first time, this paper highlights a comprehensive investigation on the effects of microwave irradiation on Canadian kimberlites. Potential contribution to the continuous rock excavation and rock weakening effect prior to implementation of mechanical techniques was explored. Two different kimberlite rocks, i.e. volcani-clastic kimberlite (VK) and hypabyssal kimberlite (HK), and granite samples were studied. Some important physical properties of the rock samples were measured including rock quality designation (RQD), specific gravity, porosity, and specific heat capacity. Rock samples were treated for various exposure times using a multi-mode MW unit at different power levels ranging from 2 kW to 15 kW. The effect of MW irradiation on rock samples was investigated. The results indicate that the mechanical properties including unconfined compressive strength (UCS) and Brazilian tensile strength (BTS) were significantly dropped as a result of MW irradiation. Finally, the effect on rock abrasivity using the Cerchar abrasivity index (CAI) has also been discussed.