A rare pink diamond discovered in Angola is thought to be the largest of its kind to be found in 300 years. The 170-carat stone, which weighs just 34 grams, has been named the ‘Lulo Rose’, after the alluvial mine where it was discovered. Alluvial means that the stones are recovered from a river bed. But the Australian owner of the mine, the Lucapa Diamond Company, says that only one in 10,000 diamonds found are pink in colour. The discovery of the pink diamond has generated quite a bit of excitement, not only within African diamond producing countries, but also worldwide. “The surfacing of thi…