This is good about why diamonds are “intrinsically worthless stones whose popularity and value are a recent creation, the result of a concerted marketing efffort by a monopolist cartel”. It talks about how De Beers have been incredibly clever in manipulating the female psyche through product placement in films and advertising to force blokes to shell out 15% of their annual income on a rock should they ever wish to get hitched. However, good luck in explaining any of this to your bird.