Abstract: A glass, in particular a glass powder, is fused from a starting mixture containing 38 wt % to 48 wt % SiO2, 15 wt % to 19 wt % Al2O3, 4.5 wt % to 11 wt % TiO2, 0 wt % to 1.5 wt % Na2O, 0 wt % to 1.5 wt % K2O and 23 wt % to 30 wt % CaO. In addition, a glass powder mixture contains a first such glass powder having a mean particle size of 150 &mgr;m to 250 &mgr;m and a second such glass powder having a mean particle size of less than 100 &mgr;m, in particular from 10 &mgr;m to 70 &mgr;m, as well as carbon black powder and an organic binder. This glass or glass powder mixture is especially suitable for producing a glass ceramic, in particular in the form of a resistor seal and/or a gas-tight glass ceramic solder in a spark plug.