One of the longest-running advertising slogans, it continues to be used worldwide by DeBeers Consolidated Mines Ltd. of South Africa.
In 1989, DeBeers honored Miss Gerety at a ceremony in London, said Chet Harrington, a friend and former co-worker at Ayer in Philadelphia.
Advertising Age ranked ``A Diamond Is Forever'' as the No. 1 slogan of the century in a special edition in March. DeBeers is now a client of the J. Walter Thompson advertising agency in New York.
Miss Gerety was a member of the DeBeers advertising campaign team at Ayer and one night was laboring to come up with a slogan, Harrington said. ``She finally wrote down `A Diamond Is Forever' on a piece of paper and put it on a nightstand,'' he said.
``When she got up in the morning and read it, she said, `I got it,' '' Harrington said.
Miss Gerety joined the advertising giant in Philadelphia in 1943 and worked there as a copywriter until 1970.
Miss Gerety, who was born in Philadelphia, graduated from the Charles Morris Price School of Advertising and Journalism and then attended the University of Pennsylvania.
Early in her career, she was an assistant copywriter for Jacob Reed's Sons.
Miss Gerety was a longtime resident of Wayne and a member of Our Lady of Assumption Roman Catholic Church in Strafford. She was a golfer and member of the Merion Golf Club.
She is survived by several cousins in Toronto.
Funeral services and burial were held yesterday.