A diamond is forever
What's the meaning of the phrase 'A diamond is forever'?
Advertising slogan for De Beers' diamonds.
What's the origin of the phrase 'A diamond is forever'?
De Beers have used this as a slogan since 1948, and continue to do so (as of 2016). Here's the announcement of the campaign, from the New York Times' Advertising News and Notes column, August 1948:
"De Beers Consolidated Mines Ltd., owner of diamond workings in South Africa, plans a fall campaign in leading national magazines which will stress the engagement-ring tradition. Four-color ads will reproduce paintings by well-known artists and carry the slogan 'a diamond is forever.' N.W. Ayer & Sons, Inc., Philadelphia, is the agency."
The slogan began appearing in the US press soon after that date, as illustrated here, from the Ohio newspaper The Chronicle Telegram, June 1950.
The notion wasn't a new one. In Anita Loos' book Gentlemen Prefer Blondes, 1925, is the line:
"So I really think that American gentlemen are the best after all, because kissing your hand may make you feel very very good but a diamond and safire bracelet lasts forever."