(IDEX Online) - Anglo American has written down the value of De Beers by $1.6bn - or 17 per cent - as reduced demand continues to drive down diamond prices.It now values the miner at $7.6bn. Anglo American took control of De Beers after buying the Oppenheimer family's 40 per cent stake in 2011 for $5.1bn. It holds as 85 per cent stake. The government of Botswana owns the remainder."Our updated assessment of global GDP growth and consumer demand were the main factors behind our $1.6 billion write-down of our book value of De Beers, principally relating to goodwill," Duncan Wanblad (pictured), CEO of Anglo American, said in the company's preliminary results for the year ended 31 December 2023."De Beers is absolutely at the bottom of a cycle and we've seen it before... and there's no doubt that as the world's GDP comes under pressure then the diamond business really does take the brunt, but it is cyclical," he told South Africa's Primedia."What we do know is that there's a return from these sorts of cycles... and in the world of natural diamonds there are very few assets, the quality of those that exist within De Beers today."Anglo American reported a 94 per cent plunge in 2023 profits to $283m across all sectors in its full year results, published on 22 February.Wanblad says the company is systematically reviewing all its assets and that nothing is off the table.