The Jonker diamond was found in South Africa on 17 Jan 1934. At 726 carats, it was the 4th largest uncut diamond ever found at the time. There is speculation that it may be part of the Cullinan diamond discovered in 1905, the largest gem quality diamond ever found, at 3106.75 carats. The Jonker was cut into 13 diamonds, with the largest an Emerald cut diamond weighing 142.90 carats.
The $1,000,000 the Jonker diamond was insured for in 1935 is equal to more than $22.5M in 2024.