Building block and method for producing the same

The invention relates to a building block and a method for producing the same, which has a reduced mass by comparison with conventional building blocks and excellent insulating properties. The building block according to the invention consists of a lightweight material which is selected from expanded glass, pearlite, expanded clay or mixtures thereof. The lightweight material is obtained by liquid phase sintering or fusing of pre-expanded glass granulate, clay granulate, pearlite or mixtures thereof and forms a pore structure as an insulating core which is at least partially enclosed by a shell body formed from a conventional building block material. The building block is produced by an appropriate shell body being filled with the lightweight material, and the pre-expanded lightweight material, which has a residual expanding agent content of at least 0.1 mass % and is used in granulate form, being heated to above the softening temperature of the granulate, an additional volume expansion occurring and the granulate surfaces being fused.