Spell scroll
Spell scroll typically refers to a treasure that can be found on the adventure map. Although it is not technically an artifact, it works in a similar way appearing in a backpack after hero picks it up, and can be equipped in the miscallaneous artifact slot. The scroll contains one spell, and as long as the scroll is equipped, that spell is added to the hero's spell book.
A Spell Scroll cannot be sacrificed at an Altar of Sacrifice.