Isn't it normally: buy their offerd export goods and sell them their needed import goods?There are actually in game hints on trading. Check the sector information on the computer in the Captains room. Trading well early requires you to pay attention, however gets easier as you progress the story.
I'm on Pleiades with 4969 credits, their export is agricultural goods, their import is manufactured goods.
So I bought 80 grain (1857 CR left).
Then head to orion (main import agricultural), sell them my inventory and got 4809 CR.
So I lost 160 CR by selling them their needed product. This doesn't make any sense to me.
Btw, titanium/beryllium aren't minerals, these are elements. Beryl or Ilmenite would be the most common related minerals to these elemtents.