Diamond no longer nature's hardest materialBeautiful, expensive and very hard. But now harder minerals have been found to exist Isifa Image Service sro/Rex Features This article was first published on 16 February 2009. See the end of the article for an update Diamond will always be a girl’s best friend, but it may soon lose favour with industrial drillers. The gemstone lost its title of the “world’s hardest material” to man-made nanomateri
