Petra Unearths 42ct. Blue Diamond from Cullinan Mine

January 14, 2026

Suzanne Watkin

Petra Diamonds has recovered a blue diamond weighing 41.82 carats from its Cullinan mine in South Africa.

The stone, a type IIb of “exceptional quality,” is the first of its color and magnitude the deposit has yielded in the past five years, Petra said Tuesday. The previous one was a 39.34-carat diamond it found at the site in April 2021. The company sold that gem for $40.2 million.

The miner is in the process of analyzing the stone and deciding the best method of sale. The Cullinan mine is known for the recovery of rare, high-value blue diamonds.

The stone is significant for Petra, which has been facing challenges due to lower demand for diamonds in the past few years. In October, the miner reported the average price it received for rough fell 13% to $110 per carat in the first fiscal quarter that ended September 30. Meanwhile the company had fully drawn its $102 million revolving credit facility as of September 30, while its net debt increased to $287 million at the end of the quarter from $264 million as of June 30.

The company also announced that same month that it had launched a rights issue in an effort to raise funds to keep the business afloat. It’s seeking approximately GBP 18.8 million (approximately $25.1 million) to continue to run the business.

Image: The 41.82-carat blue diamond. (Petra Diamonds)