De Beers Convinced Every Man on Earth to Buy a Diamond

In 1938, most men didn't propose with diamond rings. Diamonds were luxury items for the ultra-wealthy, nothing more.

Then, De Beers launched an ad campaign that would rewrite culture itself.

The Setup

Cecil Rhodes founded De Beers in 1888 after massive diamond deposits were discovered in South Africa. They had more than enough supply, but without the demand to match, circulating too many diamonds would crash prices. To drive demand, De Beers hired ad agency N.W. Ayer in 1938 with one goal: make diamonds essential to marriage.

Their tactics were both morally questionable and genius:

• Original influencer marketing — gave diamonds to movie stars, planted stories in gossip magazines about how much these stars loved diamonds.
• Psychological warfare — their famous slogan, “A Diamond is Forever,” didn't just evoke eternal love; it discouraged resales, protecting De Beers' pricing control.
• Fake trend creation — paid designers to talk about the “diamond trend” on broadcasts. Commissioned high school lecture series across America teaching kids that diamonds = marriage.
• Made-up rules — the “two-month salary rule” (later inflated to three months) was invented by De Beers to get men to spend more.

The Result

From 1939 to 1979, U.S. wholesale diamond sales exploded from $23 million to $2.1 billion, a whopping 100x increase.

Today, even with lab-grown diamonds costing 60–80% less, real diamonds remain the standard. Done right, marketing can rewrite the destiny of an entire industry.