Black and white relate to dark and light thoughts that are experienced internally.
The colors gold and iron analyze human thinking manifested externally.
Gold represents standards. The Golden Rule exhibits the best behavior possible. Golden eras are times of unison, learning and achievement. The golden rules of accounting establish ethics and etiquette for business transactions and tax recordings.
Iron represents structure. Human cells utilize iron to metabolize proteins, for DNA synthesis and to transport oxygen through the blood. Iron is utilized to create machinery. Iron is utilized to construct buildings, bridges and tunnels.