By using ultra-thin slices of diamonds, researchers have found the first direct evidence for the formation of diamonds by a process known as redox freezing. In this process, carbonate melts crystallize to form diamond. Read full article.

When David Cameron described Afghanistan to the Queen as "fantastically corrupt" over drinks at Buckingham Palace in April it was widely regarded as a gaffe. But the British prime minister was not wrong. Afghanistan ranks a woeful 166th out of 168 countries in Transparency International's latest assessment of graft and crooked dealing around the world. And there is no better evidence of just how deep corruption goes than the fate of one of Afghanistan's greatest treasures, th