Could it be possible to create a unique crystalline structure from the Bitcoin key?
This would obviously have to be impervious to reverse engineering.
If this could be done, then it would encroach on the value of gold, which is mostly for cosmetic use.
What would be the point of that? I'm curious as I can't see any at all.
Yeah, I don't see any point in this idea.
Bitcoin should stay a digital currency. I don't assume that OP means to make a physical diamond out of Bitcoin (?), but if that's true, technically physical bitcoins already exist. They're just the private key of a wallet containing a certain amount of BTC tied to some sort of physical item.