A 1947 ad campaign convinced us all that we need diamonds to get engaged, and we still believe it

If you get engaged with a diamond ring, you can thank De Beers.

The reason diamonds are the gem of choice is because of a massively successful advertising campaign from one of the biggest diamond companies in the history of the world.

In the early 1900s, diamond production was low. While giving engagement rings was a common practice, the gems weren't always diamonds. By 1938, diamonds were becoming increasingly popular for engagement rings, but then the value collapsed with the Great Depression. Still, diamonds weren't ubiquitous back then — only 10% of engagement rings included diamonds, according to the BBC.

That all changed in 1947 when De Beers launched an advertising campaign for diamond engagement rings with the slogan "a diamond is forever." As the investigative journalist Edward Jay Epstein revealed in a famous 20,000-word 1982 exposé in The Atlantic, the campaign was extraordinary in its scope.

The four-decade-long campaign changed the way the world thought about diamonds.

The company developed elaborate psychological models to plan its advertising campaign. It sought to make diamonds, with their aesthetic brilliance and unbreakable chemistry, emblematic of the eternal commitment of marriage.

"Even though diamonds can in fact be shattered, chipped, discolored, or incinerated to ash, the concept of eternity perfectly captured the magical qualities that the advertising agency wanted to attribute to diamonds," Epstein wrote.

The advertising strategy included putting "a diamond is forever" advertisements in magazines and arranging for lecturers to go to high schools to talk about the value of diamonds. By 1946, Epstein wrote, De Beers financed a weekly service called "Hollywood Personalities" that "provided 125 leading newspapers with descriptions of the diamonds worn by movie stars."

They also encouraged celebrities and socialites to wear diamonds wherever they went, imprinting the gem on the public mind as an aspirational target.

Between 1939 and 1979, De Beers's advertising budget soared from $200,000 to $10 million per year, according to The Atlantic. It was worth it. Over the same period, its wholesale diamond sales in the United States grew from $23 million to $2.1 billion. Also over that period of time, De Beers went from recommending spending one month's salary on an engagement ring to two month's.

The idea of buying diamonds spread overseas.

As Western influence grew in the 20th century, so did De Beers's advertising campaign. Traditional Japanese marriages, for example, don't include engagement rings. But following the American occupation of Japan, De Beers marketed them aggressively, billing them as a signifier of modern Western values.

By the time Epstein's exposé came out, Japan was the second-largest diamond market in the world, after the United States.

"When the campaign began, in 1967, not quite 5% of engaged Japanese women received a diamond engagement ring,"Epstein wrote. "By 1981, some 60% of Japanese brides wore diamonds. In a mere fourteen years, the 1,500-year Japanese tradition had been radically revised."

Historically, engagements weren't associated with diamond rings.

Given some kind of promissory token for marriage is an idea that has existed in many different cultures and religions for centuries.

The idea of giving a gem-studded ring supposedly originates with Archduke Maximilian of Austria, who in 1477 is said to have proposed to Mary of Burgundy with a diamond ring. But scholarship is thin on the giving of engagement rings prior to the De Beers campaign. And during Maximilian's time, nobles often proposed with different kinds of jewelry.

In Europe, using different gems were common. Prince Albert proposed to Queen Victoria in 1840 with an emerald ring that resembled a snake. But diamonds did spike in England after 1887, when hundreds of pieces of diamond jewelry were made to celebrate the 50th anniversary of Victoria's time on the throne, according to Racked.

And in America, the tradition also didn't always resemble what it does today. Women often gave engagement rings to men in the 1840s.

Norms about buying diamonds are changing.

Today, diamond rings are nearly ubiquitous. 75% of brides wear one, according to the Jewelry Industry Research Institute.

But interest appears to be waning among younger Americans, according to The Economist. They're kind of patriarchal and seem outdated in an era of greater gender equality.

More importantly, diamonds are really expensive. Younger people make $10,000 less on average and have accumulated half as many assets as Baby Boomers did at their age.

Instead, diamond companies are propped up by the growing middle classes in India and China, who still find diamonds aspirational, according to The Economist.

There is also widespread awareness of "blood diamonds," a term used to highlight the fact that diamond sales can be used to fund violence around the world.

One solution — synthetic diamonds — still aren't very popular. They account for just 1% of diamond sales, according to The Economist. And if they ever do catch on, De Beers will be fine. Its own synthetic diamond operation has more than 450 patents.

SEE ALSO: I spent 3 months finding the perfect engagement ring, and it was terrifying — but worth it

Join the conversation about this story »

NOW WATCH: Here's what those white marks on your nails say about your health