Heart of the Dawn

Wondrous item - artifact
A pulsing, metre-long, egg-shaped bundle of faceted crystal and brass. Constantly glowing with a blinding golden light, shrouded only by the segmented brass casing that seems to expand and retract over time.

If a spell that restores hit points is cast on the Heart, it pulses and releases a wave of concentrated, dangerous positive energy. Roll 4d8 for the wave’s potency – all creatures within 30 ft of the Heart must make a Constitution saving throw with DC equal to the potency roll. On a success, they are healed for that many hit points. On a failure, they instead suffer that amount of radiant damage. The Heart then falls dormant for the next hour.
The Heart also has some potential when used in crafting, which must be discovered through further research.