Sales of rough diamonds at Debswana Diamond Company fell 21% in the nine months up to September, as Botswana’s central bank data on Tuesday showed, amid global economic uncertainty and slowing demand for gems. Debswana, equally owned by Botswana and Anglo American’s De Beers, sells 75% of its output to De Beers, while the balance is taken up by the state-owned Okavango Diamond Company (ODC). Botswana and De Beers in June agreed to a new