"What Makes Diamonds So Valuable To Women" is a superb marketing campaign, for years, by the De Beers cartel of South Africa, London, and Antwerp, Belgium.
De Beers has created an artificial scarcity to keep prices up, but that control is slipping, so prices for common stones have actually fallen -- and drastically fallen if you consider that the value of the government scam fiat currencies has decreased due to government inflation of their money.
That means that a stone priced at $2000 forty years (in dollars then) ago probably still costs $2000 in today's dollars. But that $2000 forty years ago would be the equivalent of $20,000 today. AND, that stone that costs $2000 today probably would cost only $200 if the De Beers price-fixing totally fell apart.
But De Beers has done a great job marketing, making diamonds an OBLIGATION for guys "to prove their love" by buying those overpriced stones. Woe to any man engaged or married to a typical bimbo (85% of women) who doesn't get her a diamond. Nag, nag, nag. If it's a one-carat, why not a two-carat. If it's a two-carat, why isn't it a four-carat? Sob, sniffle.