[jrehor]

The Karowe mine is unusual in its high proportion of large diamonds. The only similar mine is Letseng in Lesotho. Both Karowe and Letseng have very low grade ore (in terms of carats per tonne) but high proportion of large stones. DeBeers discovered Karowe but never developed it because it was judged uneconomical; Lucara took a big bet that the quality of the diamonds would offset low yield.

I wouldn't extend the ratio of large diamonds found at Karowe (or Letseng) across the whole industry. They are fairly unique mines.