Peter Hopper has been managing director of Hoppers Jewellers, which has branches in Bourne and Grantham, since taking it over from his father, Stanley Thompson-Hopper.
Educated at Stamford School, he served as head of school and later as chairman of the Old Stamfordian Club.
Following two years of National Service as a Russian interpreter, he trained with the court jewellers in Edinburgh. He was one of the first jewellers in the country to become a registered valuer of the National Association of Goldsmiths and has held the role of president in the association.
He celebrated his retirement last week with a meal in Grantham for his employees.
Peter, 73, of South Rauceby, near Sleaford, said: "I have been so lucky and privileged to have enjoyed 50 years in the wonderful world of jewellery. I wouldn't have missed it for anything.
"I will miss the business, our lovely customers and our wonderful and dedicated staff."
He plans to spend his retirement sailing his yacht with his wife Joan and visiting friends.
He leaves the running of the business in the hands of his daughter Fiona, the fourth generation of Hoppers jewellers.