It comes from Plane of Water from the Fishlord XXXX quest.
you fight waves of anglefish mobs every 4 to 8 mobs a named spawns and can drop X random item so far I have seen a cleric earring with right click sunskin and this caster earring and some kind of boots.
The quest lasts for a bit depends on how many ppl you have in your group/raid one good group can do it, but can do it with 2 to 3 if you want just remember the more ppl you have the more mobs you have to kill to get to the last boss "king" mob
Basically I'll say it would be off the boss in SG. If my reasearch is correct there are almost NO items the drop in Elementals with less than 100hps. Sirens Grotto is my best guess. I could see it dropping from there before Elementals.
My quessing is its gonna be in the new expansion. Knowing sony to release this info but not say where and who to tease us until the gates of discord. This is just my 2cp.
I would think that this drops in the Reef of Coirnav, just like the Sharkbone Plated Shoulderpads and the Sharkspine Club. But I guess you could'nt figure that out if you also think that it was Sony released this in formation to this site.
Not too many caster earrings that beat this, considering the +12 int/wis and +115(!) mana. Focus effect is a great bonus too. Now if only someone would tell us where it drops...
Well I'm taking a guess here, says level to aquire as 65. Recommended level is 62. Since there are not that many underwater zones that reach above 60, I would say the Reef of Corniav? As for WHO drops it, lets keep guessing till someone coughs up the info =)