Don't bother with them. Really. Waste of your credits. You can barter with them in a trade, yes. But you can also barter with anything.... ships, and vehicles, and oh, Credits too. Nova crystals will cost you 50,000 but you can use them to pay most people, and you can't use them to pay the server as in building, or paying wages. Basically they are a waste of your life and Krath profits so ridiculously much from them.
Now if they didn't have a set value, and were a market price, then indeed they might be worth at least a bare minimal something, but set at a ridiculous 50,000? Yeah good luck.