A diamond jubilee is a celebration of a 60th anniversary for a person. When for a group, it is used for the 75th anniversary.
Queen Victoria's Diamond Jubilee Service, 22 June 1897
The Tolsey clock commemorates the Diamond Jubilee (60 years) of Queen Victoria's reign. The clock says "1837 – 1897". It lies between Market Street and High Street in Wotton-under-Edge, Gloucestershire, England.
Emperor Franz Joseph on the balcony of Schönbrunn Palace on the occasion of his 60th Jubilee