Why do diamonds have value then? They have no intrinsic value. They are not a scarce resource. They don't have many industrial applications. Labs can grow diamo

Why do diamonds have value then? They have no intrinsic value. They are not a scarce resource. They don't have many industrial applications. Labs can grow diamonds that look pretty much identical to the real thing. Yet people still pay a ton of real money for diamonds. Diamonds have value because we all have agreed that they have value. That's a really powerful concept to internalize. Similarly why does Gold have any value? Why does the American Constitution have any power?