Fine slag (FS), a byproduct of coal gasification, consists of mineral-rich particles (MRP) and residual carbon particles (RCP). The characteristics of the MRP were investigated by laser particle size analysis, mercury intrusion porosimetry, N-2 adsorption technique, scanning electron microscopy with energy-dispersive spectroscopy, X-ray diffractometry, Fourier transform infrared spectroscopy, and Raman spectroscopy (RS). The particle size of MRP is smaller than that of FS, which implies that the size of the MRP is smaller than that of the major RCP. MRP mainly consist of solid particles with a low porosity and contain a limited number of macropores with a pore size of 0.14-2 mu m, most of which are independent of each other inside the particles. A few crevices, holes, and round pores can be observed on the surface of the particles. The majority of MRP exhibit a comparatively smooth surface texture with debris particles adhered to the surface, whereas some MRP contain small particles embedded in the surface. The elemental distribution within most of the sphere is uniform, and organic carbon is doped into the interior of the inorganic matrix. For most of the spheres, the MRP represent a heterogeneous material comprising inorganic and organic components. The inorganic components consist of approximately 98% amorphous glass, which is a Ca-Na K Fe aluminosilicate with a highly connected network, as well as a minor proportion of quartz (2%). The organic components amount to disordered graphitic carbon, which is still more organized than RCP.