Oṃ maṇi padme hūm̐ is the six-syllabled Sanskrit mantra particularly associated with the four-armed Shadakshari form of Avalokiteshvara, the bodhisattva of compassion. From Wikipedia
Non-destructive virtual unrolling at Helmholtz-Zentrum Berlin confirmed a metal-based ink mantra on a centuries-old dharani scroll currently on display in Berlin
