Glass and glass ceramics were obtained using steelwork slag as a raw material. Glass was melted at 1500degreesC and heat treatments were performed at 720degreesC for nucleation and at 883degreesC for crystallization. Differential thermal analysis (DTA), X-ray diffraction (XRD) and scanning electron microscopy (SEM), with energy dispersive X-ray spectrometer (EDX) were used to investigate glass and glass ceramics. The crystalline phases developed were diopside and augite. The final microstructure was made up of crystals uniformly distributed, with a size of 1 to 3.5 mum.