Precious....to the Dwarves
 

What was more valued to the Dwarves? The Arkenstone, or its weight in mithril? (Any dwarf, not just Thorin).

i think the Arkenstone was worth ALOT more money wise than its weght in Mithril, Frodos Ringmail probably weighed just as much if not More than the Arkenstone, as far as Monetary value not Sentamentle Value i would say it was worth More than one 14th of the treasure in the lonely mountain Which was ALOT of Gold Mithril and Gyms. Just think that all the Treasures that Bilbo took and hid was only a fraction of his rightfull amount of one 14th.

Given that JRRT more or less describes the Arkenstone as a unique object, I would say that the Dwarves valued the Arkenstone for it's self and not in terms of it's monetary value.