Abstract: A system for stone cladding of building includes a plurality of facing blocks arranged as superposed courses. Each block in a first course has a first step defining a lower tread, a riser, and a top tread extending along the length of the top surface of the block. Each block in a second course disposed above the first course has a second step complementary to the first step and extending along the length of the bottom surface of the block and configured to interfit with the first step of a block in the first course. A plurality of horizontally-extending vertically spaced rails are attached to a wall which is to be faced. The rails directly or indirectly support the facing blocks by overriding the top tread and riser of blocks in the first course and underlying and supporting the bottom surface of blocks in the second course. A concrete layer may be poured between the facing blocks and the wall.