For example, we do gold. Pick some gold color for specular and ambient colors

Use Alternate specular for some gloss. Add granite to take edge off gloss

Use Alternate diffuse to give color when light shines. Add Clay to spread it out

Make a cloudy node and blend in other colors that are shifted by viewing angle. This will be attached to input Color of Clay node on alternate diffuse

Attach ramp of colors to Ambient node for included glowing

For reflection map, just use your favorite 2D app and create a gradient. Size depends on level of detail. I used 512x512 in this case

Save to the material library as MT5 and you can apply wherever this metal is needed