Microwave　fracturing　of　hard　rocks　holds　great　promise　in　the　civil,　mining　and　tunnelling　industries.　The　role　of　heating　and　cooling　in　the　fracturing　of　rocks　and　when　and　where　cracks　initiate　from　and　propagate　to　remain　unclear　and　need　to　be　addressed　for　future　field　applications　of　the　technology.　This　study　treated　an　alkali　feldspar　granite　using　a　6　kW　industrial　microwave　source　and　a　customised　open-ended　dielectric-loaded　converging　waveguide　antenna.　The　real-time　acoustic　emission　(AE)　characteristics　in　the　microwave　heating　and　natural　cooling　phases　were　recorded　and　investigated.　The　surface　temperature　and　P-wave　velocity　reduction　of　the　specimens　were　also　measured　to　quantify　the　thermal　damage.　The　fracturing　of　granite　is　found　to　be　tensile　failure　and　is　heating-dominated.　Although　a　considerable　amount　of　AE　hits　and　events　was　detected　in　the　cooling　phase,　they　were　of　low　energy,　and　therefore,　the　role　of　cooling　in　rock　fracturing　by　open-ended　microwave　can　be　neglected.　Fractures　initiated　from　the　exterior　of　the　antenna　and　propagated　towards　the　edges　and　the　interior　of　the　specimens.　The　cracks　obtained　from　the　AE　localisation　were　in　good　agreement　with　those　observed.　With　the　increase　of　power　level,　the　time　for　crack　initiation　was　shortened,　confirming　the　high-power　effect.