Firestone Diamonds hailed a rise in potential diamond values from its Liqhobong diamond mine in Lesotho.Firestone said an independent study of production from a pilot plant at Liqhobong had shown its base average diamond price, excluding potential large stones, increased to $107 per carat from $98 per carat beforehand.It said prices, particularly for large stones of 100 carats or more, could rise to $156 per carat.The pilot plant recovered about 325,000 carats between September 2011 and July 2013.Chief Executive Stuart Brown said: "Today's range of increased diamond values at Liqhobong is extremely encouraging, building on the solid numbers outlined by the definitive feasibility study last year."The board believes these new figures further enhance the robust project economics for the Liqhobong project." PW