Soul Print 9-14g each crystal cost 100 each
Sperion Shards 10-15s crystal cost 9 each
Using the fomula of 1s per 1 crystal you could also sell Sperion Gems, the market for unbound gems could be quite high considering the PC cost going into them. A lvl 4 gem could also include an additional cost of 20g ontop of this fomula because of the PC cost into them. Safely saying a gem that cost 1200 crystal could be worth 1.4diamond/plat in game.
If looking for buyers I can give you a quick list of ingame people with gold who would be willing to buy such things:
Maybe you could use this post as a market to sell to others in game as well. So if others come across this post maybe they can add themselves to this list. Also maybe other sellers/buyers