This paper reports on the hydrothermal synthesis of a novel 2D material, magnesium silicate hydroxide/carbon (MSH/C) core-shell nanoplate, in a graphite-MgO-SiO2 -NaOH system at 300 degrees C and 12 MPa for 48 h. Its significant potentials as an antiwear additive in lubricant oil were subsequently demonstrated. The 2D nanoplates consist of an MSH core and a 1-6 nm thick sp(2)-hybridized carbon shell with a layer spacing of 0.34 nm. In typical four-ball tests at a maximum Hertzian pressure of 3.4 GPa, the MSH/C core-shell nanoplates nearly eliminated wear, whether suspended in poly alpha-olefin oil or fully formulated lubricating oil, and the corresponding volume wear rates were reduced by 96.33% and 72%, respectively. The excellent antiwear performance was ascribed to the formation of a tribofilm consisting of diffusedly distributed Fe3O4 nanocrystals and carbon- and/or SiOx-containing amorphous structures.