I have 18 Relics. All of them I got for one reason, and one reason only - I was in the right place at the right time.
The only thing I can tell you, is kill Darkhart fast. Whether you go blunder crazy, or hit Darkhart on a popular server, the faster you kill him, the faster the loot comes, and the better the chance of you getting a Relic in a certain period of time.
Other than that, just stay at it. In time, it shall come
P.S. The Gold Room/Treasure Room is a room filled with uncollectible treasure in Toormenta. It's located at the West end of the Cursed Caverns, filled with Seabeards and Molusks.