Mirror Shard's effect should be as followed.

42954 Mirror Shard (Animal Enchantment - Armour)
When being attacked, you have a chance to increase the amount of damage your opponent takes from reflected melee and magic attacks, at a rate of 0.5% per refine.
Reflects 1% per refine of melee damage to attacker
Has a 1% per refine chance to reflect magic attacks
Increases amount of damage taken from melee and magic attacks by 0.5% per refine
Bonuses do not stack with extra Mirror Shards

However, the melee/magic reflect does not seem to be working.