I have just started to play the game and I'm having a blast.
I'm playing with a large map and with 7 opponents. I'm a little over 10 hours and half the galaxy discovered and I still haven't found durantium anywhere. No other faction has ever listed durantium when I want to trade for it. The most annoying thing about this is that the military academy requires one durantium so, so far the only way I can train legions is with training a general.
My question is, is there any other way besides legions to conquer planets? It's really painful to wait 10 turns to train 5 legions.