The star jewel seems to drop randomly off the cretures in scalet desart. I have gotten 2 off of lightcrawlers, 2 off a cheeta, and 1 off a sunflower. Don't get you're hopes up that they're common, just because I looted 5. Truth is, a guildy and I spent 40-42 out here streight. Me a SK, and him a monk. We usually had the help of our friendly neighborhood pally or cleric, but Fear kiting is definately possible.
BTW. Of all the pieces of this type of armor that I have read up on, the only piece that would really be an upgrade for me would be this mask. An arguement could be made for the helm too (Still wearing my trusty old SSB) but the mask is actually pretty nice. I personally havn't had the money or the trades to upgrade my face item. Getting quite the collection of Blood Ember, but still wearing a fine steel mask. Now, If I could only find the mark of fate........