Assuming they talk about how they prefer “real” diamonds, the latter. Similarly, people on the other side signal their association by talking about how they’d never buy “real” diamonds.
So, the consistency of the argument is just that, "I spend more for this, therefore it gives a better impression to people who also choose to pay more."
Do you keep the price tag on it?
Or do you just talk about how, obviously, you'd never stoop to buying man-made diamonds?