rough diamond

In a statement, Lucara said the stone was "one of the largest rough diamonds ever unearthed".

But even before it is in force, producers say Western customers have been shunning gemstones from Russia, the world's biggest producer of rough diamonds by volume with 30% of the market.

Becker signalled he would focus on the mental side of the game and described Rune as “a rough diamond that needs polishing.”

One of the world’s most popular types of rough diamonds has plunged into a pricing free fall, as a growing number of Americans choose engagement rings made from lab-grown stones instead.

But this rough diamond in the crown of Seattle parks is worth the effort — no gas lighting required.