Can be desynthed into a Bronze Ingot, Brass Ingot or Chestnut Lumber. If you're levelling off of these you might as well desynth as you go to recover ingots and profit off of the pricey lumber. I averaged 2 HQ3 desynths per stack of crystals - your results may vary. Otherwise, sell on AH slowly for a marginal profit or loss.
Goldsmithing can lvl up on these from lvl 20-24, you even have a small chance of creating +1 hammers. I created 2 of the + 1 version while lvling. I reccomend selling it at the guild or shop though.
very nice for level 12 whight magies, i bought mine at the market for 800 gil, not bad to me, best to look at market for good prices, good strangth if your club skill is maxed out it is very effective.