(IDEX Online) - De Beers today reported a five per cent drop in its Q2 production, but said its full-year forecast remained unchanged at 30m to 33m carats, subject to trading conditions.Output was down largely because of the planned transition of the Venetia mine in South Africa from open-pit to underground.South Africa's production was down 62 per cent compared with Q2 2022. Botswana, by far the biggest De Beers diamond-producing country, saw production increase by six per cent. Namibia was up eight per cent, and Canada was up six per cent.Total production for the quarter was 7.59m carats. Production for H1 2023 was 16.52m carats, down two per cent on 16.88m carats in H1 2022.Unit cost guidance for 2023 has been revised down from $80/carat to around $75/carat, reflecting the weaker South African rand, said De Beers in a production report."Demand for rough diamonds was impacted by the ongoing macro-economic headwinds, with high levels of polished diamond inventory in the midstream," it said.Rough diamond sales totaled 7.6m carats from two Sights in Q2 2023, compared with 9.4m carats from three Sights in Q2 2022, and 9.7m carats from three Sights in Q1 2023.The H1 2023 consolidated average realized price decreased by 23 per cent to $163/carat (H1 2022: $213/carat), primarily due to selling a larger proportion of lower-value rough diamonds, as sight holders took a more cautious approach to planning their 2023 allocation schedule.De Beers' production for 2022 was 34.6m carats and for 2021 it was 32.3m carats. Pic shows Venetia mine, South Africa