Petra Diamonds recovers 23 carat pink diamond in Tanzania

Petra Diamonds has recovered a 23.16 carat pink diamond of “exceptional colour and clarity” from the Williamson mine in Tanzania.

The diamond mining group said the stone is an example of the high-quality pink diamonds for which Williamson is known and is “the most significant recovery by Petra from the mine to date”.

It added that pink diamonds are only found in a handful of mines throughout the world and their rarity ensures they are one of the most highly coveted of all the fancy colours.

The diamond will be offered for sale by appointment in Antwerp as part of Petra's December tender process.

RBC Capital Markets said: “While we caution against attributing value to fancy colours, we would estimate a price of +$100,000 a carat based on the sale in Q3 calendar 2014 of a 16.4 carat stone for $2.2m ($134,000/ct).”

It said that suggests Petra could realise $2.3m-$3m.

“Given soft diamond prices and a still significant capex programme, the additional cash is likely to spur the equity.”

At 1125 GMT, shares in Petra were up 2.5% to 58.90p.