The association between diamonds and romantic commitment is not ancient. It was created in 1947 through an advertising campaign by N.W. Ayer for De Beers. The campaign’s slogan, A Diamond Is Forever, became one of the most effective in advertising history. It built an emotional connection between diamonds and lasting love, discouraged the resale of stones that might undercut market prices, and established a cultural norm around diamond engagement rings that spread from the United States across much of the world within a generation.
Daniel and Mom trace how a marketing campaign created what feels like an ancient tradition. The conversation covers what De Beers was trying to achieve, how the slogan worked on multiple levels simultaneously, what it reveals about how cultural norms can be manufactured, and what happens when you know the origin of a tradition you thought was timeless.
DanielMom, I was just thinking, why are diamonds so expensive? I don't really understand. Like, what makes them worth so much more than other rocks?
MomDaniel, the answer to your questions is going to surprise a lot of people, you know. It is because a big part of what makes diamonds expensive has nothing to do with how rare they actually are.
DanielThey are not actually rare?
MomThey are not as rare as their price suggests, and the story of how that happened is one of the most fascinating examples of marketing in modern history.
DanielSo tell me, how does a gemstone become far more expensive than its natural rarity alone would suggest?
MomIt starts with a company called De Beers, founded in South Africa in 1888. By the early 20th century, De Beers had bought out most of its competitors and controlled roughly 85% of the world's diamond supply. And once you control most of the supply of something, you can control the price.
DanielBy deciding how many you release and how many you hold back.
MomExactly. If diamonds flooded the market, prices would drop. So De Beers kept supply deliberately low, not because diamonds were scarce in the ground, but because releasing too many would reveal how many there actually were. You know, the sense of scarcity in the market was carefully managed, not simply left to nature.
DanielSo the rarity was partly created?
MomYes, partly. Diamonds do require significant mining effort to extract, and not all are gem quality. But the price gap between what diamonds cost to mine and what they sell for has long been shaped by controlled supply, not just by natural scarcity.
DanielBut controlling supply is one thing. How did diamonds become the symbol of love and engagement rings? Was that also De Beers?
MomAlmost entirely. By the late 1930s, diamond sales were struggling. Most Americans didn't exchange diamond engagement rings. Diamonds were seen as something only the very wealthy bought. De Beers hired an advertising agency and gave them a challenge. Make diamonds feel necessary.
MomNot just desirable, but necessary.
DanielAnd they actually managed that?
MomIn 1947, a copywriter named Frances Garrity came up with a slogan. She reportedly wasn't even happy with it herself, and her colleagues weren't impressed. The slogan was, a diamond is forever.
DanielA diamond is forever. Interesting.
MomFour words that advertising age later named the slogan of the century. The campaign didn't just sell diamonds. It created a cultural expectation, that an engagement ring should have a diamond, that the size of the stone reflects the seriousness of the love, and that diamonds should never be resold.
DanielNever resold. Why was that part important?
MomBecause if people resold their diamond rings, the second-hand market would reveal how many diamonds existed, and prices would fall. The slogan also had another effect. If people rarely resold their rings, fewer diamonds returned to the market. Whether that was a deliberate strategy or a fortunate consequence, it helped preserve the perception of scarcity.
DanielSo the slogan wasn't just emotional, it was also economic.
MomBoth at once. And it worked extraordinarily well. Within a generation, diamond engagement rings went from being something mainly wealthy people bought, to being the cultural standard. The expectation that a diamond ring is the only proper way to mark an engagement, that was largely created by an advertising campaign.
DanielSo does that mean diamonds are not actually worth what people pay for them?
MomI knew you would ask me that question. That is a genuinely complicated question. Value is partly physical. Diamonds are hard, beautiful, durable. And value is partly cultural. We collectively decided they mean something. Interesting enough, both of those things are real.
MomBut it is worth knowing that the cultural part was deliberately shaped. Not everyone knows that part of the story.
DanielSo when someone sees a diamond ring, they are seeing geology, and craft, and also a very successful marketing campaign all at once.
MomAnd the feelings people attach to them are real too. What the story changes is not the feelings, just the understanding of where some of them came from.
DanielI think knowing where something comes from makes it more interesting, not less.
MomThat is exactly the right way to look at it. So, Daniel, what is one thing you are taking with you today?
DanielLet's see. Diamonds are not as rare as their price suggests. You told me that De Beers controlled most of the world's supply and kept it deliberately low to maintain high prices. And the idea that diamonds belong in engagement rings, that was largely created by a 1947 advertising campaign with the slogan, A Diamond Is Forever, one of the most effective campaigns in history.
MomFour words that changed the way generations imagined an engagement ring.
DanielFrances Garrity didn't even like her own slogan.
MomAnd Advertising Age named it the slogan of the century.
