275 for greens, and I believe all blues as well...don't quote me on the blues. I think what you need 300 enchanting for is epics beyond 60+, but again don't quote me. I was bidding on all greens at 275 enchanting, including 70 greens. But I think to make void crystals (from epics) you need 300 enchanting..not sure about large prismatic shards, pretty sure 275 enchanting lets you DE level 70 blues.