Amantis. First, there are two Powerful "Weapons" I didn't put in:
Stormcaller - don't know if it is ancient.
Forbidden/Lost Scrolls - ancient yes, but weapon? Might put up later, when I feel like it.
The Ancient Weapon you linked to I DID talk about. IT IS NOT AN ANCIENT WEAPON. It is just titled Ancient Weapon. That is all. Look at the bottom of the OP.
Tome of Rubicon is not a weapon and it is NOT what turned the Dwarves into stone - the Hammer of the Great Dwarf did (and I did forgot that, when/if I add Stormcaller and the Forbidden Scrolls, I'll add the Hammer of the Great Dwarf).