Here's a thread describing how common these are becoming. I would start to think of these as a Chaos Axe, but with a perfect green cousin that kills its value.
I bought it a couple of days ago for 3k, as i was looking for a cheap elemental damage sword.
At first it was unidentified and i got the seller to identify it, he wanted to sell it for 5k but i said no then he said 3k. I bought it but failed to notice it was < 50%.
I'm glad i didn't pay anymore for it, i'll flog it to someone for about the same.