A cementitious compostion for high density, low porosity sheet-form building materials having solid surfaces is comprised of cement, pozzolans, and a high percentage of fine andor coarse glass aggregate. In one embodiment of the invention, the panels are seamless, one-piece members integrally formed from a single resinous material. The degree and distribution of oligomerization varies upon the type and concentrations of different reaction mixtures utilized and upon the length of allowed reaction time. The indexes and the pixels have different optical reflection features. The ratio of width of each pole gap and distance between pole pieces of the first and second magnetic gaps along the direction of ion emission is not less than 0. The cooling channel is confined by the recess bottom surface of the recess and the inner surface of the insert block.