On Next Island we have a lot of crystals, some no longer drop (I will not list these, too many to name and no point listing if they don't drop). Some are used Raw some are Refined. Rule of Thumb DO NOT REFINE (update) Crystals can now be turned back by putting them back in the refiner!! unless you know why you have refined it or are going to use it for that purpose. Crafters like to buy the raw form because they are needed for certain blueprints.
List of all Crystals