The batch compositions and physical properties of slag-ceramics were studied with respect to their formability from the molten state and conditions of nucleation and crystal growth treatment. The selected batch compositions for nucleation and growth studies were slag, 56%; silica sand, 28%; $Na_2O＋MgO$, 8% and $TiO_2＋$chromite, 8%. The optimum nucleation condition was the temperature of 75$0^{circ}C$ with 6 hrs. holding time and the optimum growth condition was the temperature 975$^{circ}C$ with zero holding time. The slag-ceramics prepared under the above conditions showed the best developed microtexture. The grown crystals were identified as diopside with the average grain size of 5.7$mu extrm{m}$, and the amount of crystal grown were about 53% by weight. The prepared specimens of slag-ceramics showed the microhardness, 793kg/$ extrm{mm}^2$; MOR, 1,050 kg/$ extrm{cm}^2$ and thermal expansion coefficient, $85{div}10^{-7}$cm/cm/$^{circ}C$($25^{circ}C$~$700^{circ}C$).