Angrist was a knife held by Curufin and then Beren, of which was said that "iron it would cleave as if it were green wood".

1. History:

Angrist was made by the dwarf-smith of Telchar for the Elf-lord Curufin in the First Age. It was worn by him, sheathless by his side, when he and Celegorm attacked Beren Erchamion and Lúthien Tinúviel in the forest of Brethil, attempting to kidnap the latter. The brothers lost the fight and the knife, along with other spoils, was taken from Curufin.  

During the Quest for Silmaril, Beren used it to cut through the Iron Crown of Morgoth and free a Silmaril. However, its blade snapped as he tried to cut a second jewel and Morgoth stirred as a shard grazed his cheek. Beren left Angrist behind as he escaped.

2. Etymology:

Angrist means "iron cleaver" in Sindarin (from ang = "iron" and crist = "cleaver", "sword").