Bloodstone Chalice

The Bloodstone Chalice is an item in The Elder Scrolls V: Skyrim. This item's first appearence was in the Dawnguard DLC expansion pack. After you complete the cooresponding quest for the Volkihar Vampires, you will be able to activate this item on a table in the Volkihar palace which gives the Dragonborn an active effect called "Blood of the Ancients". This makes your Vampiric Drain spell absorb stamina and magicka along with health for 1 day (you can later make the duration longer during a quest you can get from asking for work from the vampires around Castle Volkihar).

Once the Dragonborn has killed Lord Harkon in the questline, in the chest inside the room where you kill him in, there will be two more Bloodstone chalices that can be put into your inventory, these are not quest items so they can be removed from your inventory. If you drop one, it floats in midair (this may be a glitch) the Dragonborn can jump onto the floating chalice and reach higher places in which you couldnt do before. (Ex: You can jump onto the chalice then onto Mercer's Roof in Riften, then you can hop onto the balcony and et into his house before the quest from the Thieves Guild). If you go into his basement you can find the glass sword, chillrend (overpowered at low levels), and take it.
 * Spoiler Alert*