So, I noticed there weren't any threads about this, and decided to try to get out of leecher rank.
I don't know if it's common sense, but here it goes:
So, you make a Brilliant Glass and get a Dawnstone or Talasite that sells for a bad price? Just close the Glass window when you look at it rather then looting the gem, and sell the Brilliant Glass for ~25-30g.
I've done this and made a good chunk of gold off those worthless talasites.