To resolve the problem with construction of walls or fences from piled up concrete blocks that the walls or fences thus formed are too heavy leading to poor productivity, by using resin blocks for lighter weight and easier handling and to provide the feeling of stone and enhance fire resistance by providing pumice or the like on the surface of a wall or fence.

Pumice, quartz sand and other minerals are pulverized and a resin and clay or cement or the like are admixed and applied to a mold as a binder. A raw resin comprising unsaturated polyester resin blended with calcium carbonate is blended with an inorganic pigment and reinforced with glass fibers and is applied to the block-shaped mold by hand lay-up.