I think there's something broken with this crafting shard. Natural Armor is a suffix (shard of Natural Armor), however, when I try to add the shard to an item that has a prefix, I get the error "item already has a suffix" (which it doesn't) and I'm unable to add the Natural Armor. If I add the Natural Armor shard first, it's added as a suffix (as it's supposed to) and I'm then able to add the prefix no problem.
I've search the forums and someone mentioned something similar in another thread, but I thought I'd point it out here in case it wasn't picked up.
Anyway, this isn't a huge deal, but I hope the devs are aware of it.