The Dagger 'Nimthanc' (2d4) (+9,+12) [+10]
Branded with frost. Provides resistance to cold. Cannot be harmed by acid, electricity, fire, cold.
When aimed, it creates a frost bolt with damage 6d8. Takes 8 to 15 turns to recharge.
Min Level 1, Max Level 50, Generation chance 40, 1.2 lbs

(Angband 3.1.2v2)