Shamshir-e Zomorrodnegar

Shamshir-e Zomorrodnegar (Persian: شمشیر زمردنگار) "The emerald-studded sword" is a sword in the Persian legend Amir Arsalan. The witch mother of an hideous horned demon called Fulad-zereh, used a charm to make Fulad-zereh's body invulnerable to all weapons except the blows of a specific sword called Shamshir-e Zomorrodnegar.

This blade originally belonged to King Solomon, and was carefully guarded by Fulad-zereh, not only because it was a valuable weapon, and indeed the only weapon that could harm the demon, but also because wearing it was a charm against magic. A wound inflicted by this sword could only be treated by a special potion made from a number of ingredients, including Fulad-zereh's brains.

References

*Encyclopaedia Iranica