Looted one of these on a restless crocodile (mob name?) in the Loping Plains (SoF zone), so it seems it's been spread out a little bit more than it was, and will probably become cheaper (maybe not).
I would not sell these to the local vendors for any 571p. They make some awesome jewelry with 20ac, 175 mana/hp/end. They also have two augment slots :)