The question itself if frought with issues. Firstly, ORIGINAL clovers are naturally possessed of only three leaves. Therefore, finding a four-leaf clover was extremely rare (it would have to be a mutation) and therefore lucky. But now-a-days four leaf clovers have been genetically engineered, so you can go to any garden centre a by a packet of "Four leaf clover" leaves, which I think traditionally defeats the purpose behind its magic. I think if you where to find one in the wild, and you where to remove one of its leaves, this would be unlucky. But the storebought variety holds no magic in my eyes.