Value is not an intrinsic property of a thing, but is determined solely by what someone is willing to pay you for it. I agree that the value of diamonds is an engineered one, but it still doesn't change the fact that people will pay truckloads of money for them.
> Value is not an intrinsic property of a thing, but is determined solely by what someone is willing to pay you for it.
Well, that's the thesis of the article I linked: out there, in the free market, you wouldn't get much if you'd try to sell a diamond and weren't part of the supply chain.