Heart of the Furnace is an Artifact Set with maximum 5 star rarity in Genshin Impact.

2-Piece Bonus

Increases the equipping character’s ATK by 12% for 12s when they trigger a Stellar Glimmer reaction or deal Stellar Glimmer reaction DMG. Also increases Stellar Glimmer reaction DMG dealt by all nearby party members by 50%. The above effects can trigger even when the equipping character is not on the field, and the DMG bonus from multiple Artifact Sets with the same name do not stack.