Petra Diamonds has announced it has recovered a 23.16 carat pink diamond of "exceptional colour and clarity" from its Williamson mine in Tanzania. The company said this is the "most significant recovery" by Petra from the mine to date. "Pink diamonds are only found in a handful of mines throughout the world and their rarity ensures that they are one of the most highly coveted of all the fancy colours," the company said in a statement. The diamond will be offered for sale in Antwerp as part of its December tender process. Shares in Petra Diamonds were up 4.4% at 60.00 pence Friday morning.