Well, they have a variety of golds. They used to have a bright gold called Burnished gold. Not one of my favorites, because its.....too bright for me. They now have shining gold, dwarf bronze and tin bitz.
To get a true bright gold using the Shining gold, believe it or not base paint the area in mithril silver. The bright undercoating will really bring out the gold color. And for that extra shine you could mix in a glaze medium.
Adeptus Astartes Commandments
1. Thou shalt not replace the Librarian's staff with a magic wand.
2. Though shalt not refer to thine brethren, whom the Emperor has dictated be armed with an incendiary weapon, as a "Flamer" constantly. For this has been proven to lower morale and cause strife within His Most Holy showering facilities.
3. Thou shalt not follow a Librarian around thinking, "Can you hear me now", repetitively in an attempt to drive him insane.