In 1947, Ayer copywriter Frances Gerety came up with the slogan ‘A Diamond is Forever’ and the association with eternal love was solidified. It’s appeared in every De Beers advert since 1948. It’s been heralded as the ‘advertising slogan of the century. It was so successful Gerety worked on every De Beers campaign until 1970. Shortly after it was immortalised in the Bond film of the same name. What the slogan did was create the concept that a diamond ring would be kept by the betrothed for eternity, creating a special sentiment but also meaning fewer would be re-sold, therefore increasing the chance for De Beers to sell more, freshly mined stones. Ayer’s copywriters were also skilled in directing consumer spending habits suggesting a month’s salary was a good amount to spend on a ring, then upping it to two by the 1980s. Before the second world war, 10% of engagement rings contained diamonds. By the 1980s the number was up to 80%. Over the same period, diamond sales in the United States grew from $23 million to $2.1 billion. De Beers and N.W. Ayer & Son’s marketing masterpiece played on our emotions so powerfully that not only were they able to sell us a product we didn’t need but they influenced the culture of marriage.