+2 soul hearts. While Isaac has no empty red hearts, grants 2x damage, +5.25 range, and -0.3 shot speed. Regardless of health, the crown deactivates for the current room when Isaac takes damage.
Quote
"The untainted gain power"
Effects
Grants 2 Soul Hearts.
Replaces normal tears with blue diamond tears while Isaac has no damaged Red Heart containers or Bone Hearts.
This includes whenever Isaac doesn't have any Red Heart containers.
The coin health of Keeper and Tainted Keeper count as red heart containers for the purposes of this item.
While the effect is active, grants double damage, +5.25 range, +0.5 tear height and -0.30 shot speed.
The crown will glow blue while active; if inactive, it will appear grey.
The effect will deactivate for the rest of the current room when damage is taken, regardless of Isaac's health.
Synergies
Holy Mantle - This will block damage and keep Crown of Light active.