Unique Items worth 5000+
Name: Spell Breaker
Type: Shield
Armour Rating: 70 (Base)
Condition:
Weight: 25.0 (hEAVY)
Value: 115000
Cast When Used: ???
  Silence for 30 secs in 30 ft on Target
  Reflect 10 to 20 % for 30 secs on Self
Charge: 1800
Quest Related?: ???
Location: Bthuand
Getting it:
Travel to the fortress Rotheran, south of Dagon Fel. From there head south a few sectors until you reach a Daedric Shrine then go west to the Dwarven Ruin of Bthuand. Look around for a room with a dead adventurer, then look where the walls have collapsed. There should be a pile of bones and behind that is the Spell Breaker.
NOTE: I could not see this artifact in game even though it was plainly there in the editor. Maybe someone can shed some light on why it's not there for me. Is it a bug? Maybe it only appears after accepting a quest?
Bthuand - Exterior
Bthuand - Interior | Spell Breaker location