Abstract: The invention relates to a foamed glass plate which has a dense glass surface layer on a foamed glass layer and which is useful as a building interior material or a furniture material. The interface between the two layers is made wavy, and the dense glass surface layer is made transparent or translucent so that a wavy pattern can be seen through the dense glass layer. For example, the interface is corrugated or rippled. The foamed glass plate can be produced by the steps of layering a granular material of foam glass on a conveyor belt made of a heat resistant material, desirably waving the upper surface of the layered material, overlaying the waved surface with a layer of a granular or powdery material of dense glass and firing the materials in layers on the belt in a furnace.

Abstract: The invention relates to a foam glass block provided with a dense glass surface layer. To solve a problem that adhesion of the dense glass layer to the foam glass layer is insufficient, a relatively thin intermediate layer of porous glass is interposed between the basic foam glass layer and the dense glass layer. The intermediate layer has apparent specific gravity of 0.8-1.8, whereas the basic foam glass layer is lower than 0.8 in apparent specific gravity. The multilayer foam glass block is produced by simultaneously firing a granulated material of the basic foam glass, a granulated material of the intermediate porous glass and a particulate material of the dense glass in layers, or by firing a granulated material of foam glass and a particulate material of dense glass in layers and pressing the upper surface of the dense glass during or soon after firing.