Final answer:
Erasmus Jacobs was the name of the 17-year-old shepherd who discovered a large diamond on the banks of the Orange River, leading to significant developments in the South African diamond mining industry.
Step-by-step explanation:
The 17-year-old shepherd boy who discovered an 83.5 carat diamond on the banks of the Orange River was Erasmus Jacobs. This discovery is historically significant as it was one of the events that contributed to the diamond rush in South Africa and the eventual establishment of the diamond mining industry there. One of the most notable figures in this industry was Cecil Rhodes, who, after starting in diamond mining, founded the De Beers Company and gained a near monopoly on the world's diamond production. The reference to Fitz-Norman and the fantastical diamond discoveries in the provided information is not historically accurate as they originate from F. Scott Fitzgerald's fictional story 'The Diamond as Big as the Ritz.'