CCTV footage hailed as “amazing” by the shop’s owners shows Andy Fiddler, 52, tearing off his jacket and tackling the man during the raid at DJM Goldsmiths in Preston, Lancashire.
The thief, who had his face covered, jumped over a counter and rummaged through on-display jewellery, according to the shop’s owners.
He was then restrained for four minutes until police arrived.
Mr Fiddler was browsing for an engagement ring with his fiancee when he tackled the thief.
Gary Shaw, 55, who has co-owned the shop since 1982, hailed Mr Fiddler’s courage as “fantastic”.
The incident on January 13 was the shop’s fourth robbery in its 35-year history, Mr Shaw said.
“We’re only a small company, we work for 35 years, and we’ve worked damned hard, and we feel it doesn’t give somebody the right to decide that they want to take our hard-earned stock.
Co-owner David Mounsey, 70, added that Mr Fiddler “didn’t hesitate”.
He also said the jeweller’s staff were amazed by the CCTV footage of the incident.
Aaron Jameson-Kennedy was jailed for 16 weeks and fined £115 after pleading guilty to robbery at Preston Magistrates’ Court.
