Cover of the Book of Kells

Origin
The Book of Kells, or the Book of Iona, was written around the year 800 CE, either at the abbeys of Iona, Kells, or partially at both locations. During a Viking raid on the latter, the book’s cover was torn off and stolen, though the pages survived.

Effects
When opened, the interior radiates a holy light that restores one’s faith. However, the gazer must take care not to look for too long, lest they be consumed by it until they spontaneously combust.