As another person suggested, value is like beauty; in the eye of the
beholder. I suggest it has to do mostly with rarity of the moment.
Long ago there was a question whether a gentleman should buy as an
heirloom an article made in the choice of two metals, both newly
discovered, both rare, both expensive. Platinum or aluminium?
Unfortunately for his heirs he chose aluminium. And how much is a
bucket full of diamonds worth when you are dying of thirst in a vast
desert? Or a bucket of water? Rarity of the moment, eh? The answer
to the question “How much is it worth?” is simply “whatever you can
get for it”. Or, “What is the going rate?” –
John Burgess; @John_Burgess2 of Mapua Nelson NZ