[The Saucepan Man]

OK, in an effort to resolve this impasse, I shall make a guess. [img]smilies/tongue.gif[/img]

Dwarves had a hand in the making of all of them except Gurthang.

Anduril or before it was reforged Narsil: Narsil was forged by the Dwarf-smith (and renowned forum member [img]smilies/wink.gif[/img] ) Telchar.
Thingol’s Silmaril: was fashioned into a necklace, the Nauglamir, by Dwarves.
Dragon-helm of Dor-lómin: was also made by Telchar, a Dwarf.
Nenya: was made of mithril which, presumably, was mined by Dwarves.
Arkenstone: was mined, and thereafter fashioned, by Dwarves.

Gurthang, on the other hand, was forged by the Elven-smith Eol, and no Dwarf had a hand in its making.