Shares in Gem Diamonds were sparkling after tit announced that a 'remarkable' 185 carat rough white diamond was recovered from its Let?eng mine in Lesotho at the end of October.It is the second big diamond to come out of the mine in about two months. On August 24 it retrieved a 196 carat white diamond.Early examinations indicate that this rough diamond will yield top colour and top clarity polished diamonds and is thus expected to achieve a substantial price per carat, said Gem of its latest discovery.'Let?eng is one of the world's truly extraordinary diamond mines and its reputation is well deserved given the frequency with which it produces remarkable diamonds,' chief executive Clifford Elphick said.