Varda Shine and Bernard Pryor will join the board from January 1, 2019, in accordance with the Petra nomination committee's three-year succession plan.
Shine has been in the diamond industry for 30 years and was previously CEO of De Beers Trading Company.
She was the first woman to be awarded honorary lifetime membership of the Israel Diamond Exchange, received the Women's Jewellery Association Hall of Fame Lifetime Achievement Award in 2011 and was made an honorary member of the London Diamond Bourse in 2014.
Shine also sits on the Boards of Lonmin, the Mineral Development Company Botswana and Sarine Technologies.
Pryor is currently CEO of Alufer Mining and non-executive chairman of MC Mining Limited.
He was previously CEO of African Minerals and Q Resources and also held senior positions with Anglo American and Adastra Minerals during his 35-year mining career.