Level 8 magic item, doesnt occupy any item slots.
Varying is size from ring-sized gemstones to pieces almost as big as a halfling. These shards were once part of the Bloodstone of Karsus, shattered by the Spellplague and scattered across the Northern Realms.
Regardless of size, each piece empowers its wielder as if they were standing upon bloodstone (score a critical hit on a natural die roll of19 or 20) and if the wielder has an infernal background (infernal/dark pact warlock, devilish heritage, or Netherese origin), it will automatically grant a +2 power increase to all dice rolls (in addition to existing implements/powers). The Shard does not have to be held to be in effect, just on the wielders person.
It is rumoured that certain power groups of the North are actively seeking any Shards that are revealed, though whenever any have been reported they have mysteriously dissappeared (along with their wielder).
The shard the party have found in the duergar temple fits in the palm of the hand and weighs 3lbs.