Two cubes are associated with the rhombic triacontahedron (RT). The edge of the larger cube is 1.618... (the golden ratio) times larger than that of the smaller cube. The smaller cube is inside the RT, and its vertices are vertices of the RT. The larger cube is outside the RT, and its faces are in the same planes as six faces of the RT. The RT fits in a golden rhombus. When such rhombi are joined to form the faces of a larger RT, then the associated RTs are joined face to face.