N. W. Ayer & Son created one of the most recognized slogans of the 20th century, A diamond is forever.
Harry Oppenheimer of De Beers and Ayer president Gerold M. Lauck discussed a marketing campaign in 1938 that would change the falling price of diamonds at the time. The idea of engagement rings decorated with diamonds wasn't very popular in Europe, but interest in diamonds was high in the U.S. Because of this, Oppenheimer decided to promote the idea in the U.S. and told Lauck that, if Ayer's plan was successful, De Beers would have Ayer become the exclusive agency for its American interests. Ayer was motivated to propose that its campaign should move the American spending demographic towards larger and more expensive diamonds.
To successfully achieve its goal, Ayer suggested a reinforcement of the relationship of diamonds with love and romance. This proved successful, as both men and women were caught in the relationship of diamonds being a gift of love. The slogan created for De Beers remained memorable for many years.