INFOGRAPHIC: Five biggest diamond heists in 10 years

A range of economic and political issues seem likely to keep investors interested in adding gold to their portfolios.

Copper futures edged higher in London and New York as tentative signs of buying interest emerged following a string of losses.

Toronto-based Mandalay has used revenue from its Bjorkdal gold mine in Sweden and Costerfield gold and antimony mine in Australia to accumulate $55 million in cash.

Prices for nickel, used in stainless steel and batteries, dropped towards $15,000 a ton on the London Metal Exchange.