A method of making a building block from clay-containing compounds, which includes employing a major amount of such clay-containing material in combination with a calciferous additive and water to cure the shape the same under the influence of controlled pressure and temperature for a pre-determined time to create building block which is characterized by a mineralogical crystalline phase. The clay-containing compound includes a mixture of fine particulate material and coarser particulate material. The product produced by the method is also disclosed.