User blog comment:Shinen-san/Shard, the Mirrorborn/@comment-1618239-20120418160854

Why would unique properties be omitted from the passive? Manamune's mana gain seems like it could be fine, even interesting.

Chalice would never activate, though; neither would the Manamune AD gain from mana. Your passive says, instead of gaining mp5, you gain hp5; instead of gaining mana, you gain health. It mentions nothing about what happens when an item tries to access your current mana, checking it to give you special bonuses.

Also, mp5 costs a lot more than hp5. I think.