I don't recall seeing anything that said we couldn't do this so- I'd like to trade some of my Flight Riseing gems for Sylestia treasure/gems.
Seeing as you can buy both for $ but don't have to we can find a common exchange unit.

Looking at the Diamond shop on Sylestia it looks like it's $5 for 500 but due to the sale you get extra (going by the first package) which should mean the same as Flight Rising (feel free to correct me if I am wrong)

I normally use my FR and Ovi funds on art for my characters but I haven't bought art in quite a while and I think I'd really like to catch up a little- I had taken a huge year or two long break from this game and came back right before the event started.

Looking for gold only no diamonds- will trade my diamonds though for gold (but only for around broker price ;^^)

My exchange units;

Flight Riseing
Gems 1 - 1,000 Treasure
(I forget the Ovi exchange rate atm) I have around 1,010 credits