That was interesting, thanks.
I was at a talk some years back where the lecturer mentioned, almost in passing, that in medieval times precious stones were used in cookery because of their perceived medicinal and magical powers. Like an idiot I didn’t think to corner him afterwards and insist on having more information about it — eg did they put them into the meals by shaving bits off, or just waft them over the food with some kind of blessing ceremony? I’ve never heard or read anything of the kind again, though, so I’m not even sure now whether he was having us all on!
One thing I do know about diamonds, though, is that they weren’t valued as much in Elizabethan times as you might expect given their pre-eminence as precious stones now, because the faceted cuts which give them their brilliance hadn’t been developed, so they weren’t as immediately striking. Elizabeth herself favoured pearls, I think, because of the purity idea, as befitted the Virgin Queen.