RAPAPORT... Petra Diamonds' revenue jumped in the three months ending September 30 as rough prices grew and the company sold inventory it couldn't shift during the peak of the Covid-19 crisis.Sales rose 33% year on year to $82 million during the miner's first fiscal quarter, while sales volume increased 55% to 936,749 carats, the company reported Tuesday. Prices at its September tender were 21% higher than in March and April and rose a further 2% in October.Production fell 10% to 974,346 carats for the quarter, mainly due to the continued shutdown of the Williamson mine in Tanzania. The company is still not forecasting its future output because of uncertainty around the pandemic."While the mines are generally operating at planned levels, there remain risks to production relating to the impact of the stringent Covid-19 measures in place," the company explained. Production increased at the Cullinan and Koffiefontein mines, but fell at Finsch. Prices are still 10% below pre-pandemic levels, despite the recent improvement in the diamond market, Petra added. The company will remain flexible with the timing and method of its rough tenders for the rest of the fiscal year ending June 30, 2021.Image: Loaders collecting ore at the Finsch mine. (Petra Diamonds)