Decent little item for the cost. With maxed-out crit AA's I got this damage out of one cast on a bear:
2000 8200 2000 8200 8200 8200
That's 38,800 mana-free damage. And it's an ice DOT, which druids don't normally get!
Downsides are it's recast timer is long (4 mins 10 secs) and it's on the same timer group as the mana-free fire aoe dd (Fireshard Ring) and the mana-free magic dd (Etherbolt Ring) so you can't cast all 3 at once, which would be uber. Etherbolt is only 5k, and comes with a knockback and tossup, which could be situationally disastrous. Fireshard is a 7500pt DD but it's aoe and has a pushback which is a purely situational spell.
So I'd suggest acquiring all 3 items, since they should be cheap, each requiring 3 Ethernere Essences, a steel ingot and a gem (Diamond, Blue Diamond or Star Ruby) to make. Use the earring for steady extra mana-free damage and the other two when you can use a pushback effect.
Where such items can really shine is with a boxer. I box 6 and I'm throwing one of each on all 6 toons. As long as I can remember to click them that's a lot of mana-free damage in a single encounter.
The trivial isn't bad either. I had 6 failures while making 18 of them and with salvage I recovered a lot of my mats in those failures.