Micromechanical　characterization　of　brittle　ceramics　remains　challenging　due　to　the　difficulty　in　sample　preparation　required　by　conventional　tests.　The　micromechanical　properties　(e.g.,　elastic　modulus　E　IT　,　indentation　hardness　H　IT　,　and　fracture　toughness　K　IC　)　of　ZrO2　2　and　Si3N4　3　N　4　were　investigated　by　indentation　and　scratch　tests　with　different　indenters　(e.g.,　Vickers,　Knoop,　and　Berkovich　indenters)　under　various　loads.　The　ratio　of　the　true　hardness　by　the　Vickers　indenter　over　that　by　the　Knoop　indenter　is　approximately　a　constant　of　1.13　and　independent　of　material.　Elastic　recovery　of　residual　imprint　by　the　Knoop　indenter　was　also　used　to　assess　elastic　modulus　of　ZrO2　2　and　Si3N4,　3　N　4　,　and　modified　equations　were　proposed.　The　length　of　Vickers　indenter-induced　cracking　was　found　to　be　proportional　to　the　applied　load　under　large　loads,　and　a　modified　formula　for　calculating　fracture　toughness　was　proposed　for　ZrO2　2　and　Si3N4,　3　N　4　,　which　have　relatively　large　fracture　toughness　of　about　9　MPa　&　sdot;m1/2.　&　sdot;　m　1/2　.　The　critical　void　volume　fraction　f　*　in　the　nanoindentation　energy-based　methods　was　found　to　linearly　decrease　with　the　exponent　m　f　of　the　power-law　equation　used　for　curve　fitting　of　the　degradation　of　H　IT　or　E　IT　with　h　max　.　The　determination　of　fracture　toughness　by　scratch　methodology　was　found　to　be　affected　by　mechanical　properties　of　material,　indenter　geometry,　and　data　range.