The world's largest diversified resources company BHP Billiton has become less diverse after exiting the diamond mining business.
BHP confirmed speculation first aired several months ago that it would sell its EKATI diamond business in Canada to Canadian miner and jewellery retailer Harry Winston Diamond.
The sale price is $US500 million ($A481.58 million) but BHP said it would also book a non-cash impairment charge of about $US200 million ($A192.63 million) on the asset's carrying value.
The move is consistent with a desire by BHP under chief executive Marius Kloppers to strip away and simplify the business.
That involves disposing of its smaller or less-profitable divisions with challenging outlooks, including nickel and aluminium.
BHP chief executive non-ferrous Andrew Mackenzie said the sale was consistent with a focus on large, long-life, low-cost, expandable, upstream assets.
"Together with the recent sale of our interests in Richards Bay Minerals (mineral sands) and Yeelirrie (uranium), (the sale) reflects our ongoing pursuit of a simpler business," he said in a statement.
It sees its future core assets being iron ore, coal, copper, petroleum and potash, although some analysts warn the world can change quickly and its other assets hold hedging value.
The diamond mine is located in Canada's remote northwestern territories, 200km south of the Arctic Circle.
Rio Tinto has also put its diamond assets up for sale.