Wouldn't the value of gold and diamonds in that case be instrumental value, not inherent value? They are valuable by virtue of the aesthetic pleasure they cause in onlookers, or in their use as drils, and so on, where something with inherent value would be worth sustaining and creating even if it served no further end, like the life of a person for example.
I dare say you're right; never got far with Kant beyond the Imperatives - you appear to use his definition from within value ethics. My assessment was closer to the use in economics but still a bit aberrant - the context was the comparison of the value within the exchange articles themselves across paper money, gold, and cryptographic currency. The essence of my argument is that there is nothing else to be done with non-physical "articles" of exchange.
One might argue that the use of crypto hashes to certify documents or perform escrow-like services is comparable to the physical utility of gold and "paper" money. That seems a more apposite objection to my point, but hey ...
