Scarcity, fungibility, divisibility, durability are not societal constructs. Plus all metals have some inherent value. On top of that you have desirability which you could perhaps explain as a societal construct although I think there is something ingrained in the human psyche about valuing very smooth and shiny things (perhaps there is even an evolutionary explanation). At any rate a societal construct that has persisted for milenia across vast swathes of the globe is not your typical societal construct.