Rare Metals would be a lot more Useful - and have less BAD effects on the Economy.
Look for a Star System with lots of Useful Metals - in very large quantities. Could be Planets - but if deep down, then Asteroids ae easier to Mine.
Imagine mining Mega Tonnages of - Platinum ( such a Waste to use it for Jewellery ), Rubidium, Rhenium, Rhodium ( likewise Re Jewellery ), Tungsten, Vanadium, Niobium, Molybdenum, Beryllium, and lots more which are Very Useful.